Reversed and remanded by published opinion. Judge MICHAEL wrote the majority opinion, in which Judge MURNAGHAN joined. Judge WILLIAMS wrote a dissenting opinion.
OPINION
MICHAEL, Circuit Judge:William Runnebaum, who is infected with human immunodeficiency virus (HIV), the virus which causes acquired immune deficiency syndrome (AIDS), appeals an order of the district court granting summary judgment in favor of NationsBank of Maryland, N.A. on Runnebaum’s claims of discriminatory treatment under the Americans with Disabilities Act (ADA) and the Employee Retirement Income Security Act (ERISA). See 42 U.S.C. § 12112 et seq.; 29 U.S.C. § 1140 et seq. We reverse and remand for trial because we find that issues of material fact preclude summary judgment.
I.
Because this case comes before us after a grant of summary judgment, we must construe the facts in the light most favorable to the non-moving party, here Runnebaum, and we must draw all justifiable inferences in his favor. Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 255, 106 S.Ct. 2505, 2513-14, 91 L.Ed.2d 202 (1986); Smith v. Virginia Commonwealth University, 84 F.3d 672, 675 (4th Cir.1996) (en banc); Amirmokri v. Baltimore Gas & Elec. Co., 60 F.3d 1126, 1134 & n. 3 (4th Cir.1995). This is because “at the summary judgment stage the judge’s function is not himself to weigh the evidence and determine the truth of the matter but to determine whether there is a genuine issue for trial.” Anderson, 477 U.S. at 249, 106 S.Ct. at 2510 (quoted in American Metal Forming Corp. v. Pittman, 52 F.3d 504, 507 (4th Cir.1995)). Read in the light most favorable to Runnebaum, the record discloses the following.
In June 1991 NationsBank in Baltimore hired Runnebaum away from First American Bank, where he had worked in private banking and had been a branch manager. In his first year at NationsBank Runnebaum *1288worked in the private banking department, where he served as marketing coordinator. When NationsBank’s Baltimore operation opened a new trust department, Runnebaum applied for a sales position in the new department. Under NationsBank policy Runneb-aum could be considered for another position only if he was “performing at a satisfactory level or above in [his] current position.” Runnebaum’s supervisor in private banking, Michael Kines, recommended Runnebaum for the new job in the trust department. Kines said that Runnebaum had “good skills and is a valuable member of the PB [private banking] team.” In particular, Kines said that Runnebaum had “[g]ood calling skills and planning ability” and that he did especially well on “marketing oriented” projects. After a series of interviews Ann Pettit, the trust department supervisor, hired Runneb-aum in June 1992. At the same time Pettit hired Clifford Andersson to work in an identical position at NationsBank’s Bethesda, Maryland, office. Pettit required both men to sign a “sales goal” letter that set sales targets for the remaining months of 1992. Runnebaum and Andersson also received a “Training Tasks” memorandum from Pettit, dated July 14, 1992 (the “July memorandum”).
In August 1992 Runnebaum made his first sale, bringing to the bank $2.55 million in assets to administer. In September Runneb-aum made a second sale that brought in nearly $500,000 in assets. In October the bank gave Runnebaum responsibility for planning a reception for lawyers from McGuire, Woods, Battle & Boothe. This was an important marketing event because lawyers (dubbed “external referral sources” by Pettit) at times referred their clients to the bank’s trust department. The McGuire, Woods reception went well, and Michael Brown, NationsBank’s Baltimore city manager for the trust department, sent Runnebaum a handwritten “note of thanks and congratulations.” 1 On November 6,1992, Pettit gave Runnebaum responsibility for planning and hosting the bank’s “Greater Baltimore Holiday Reception,” scheduled for December 15. This was a major marketing and customer relations undertaking, on which the bank spent more than $10,000. Formal invitations were sent to clients, prospective clients, and those who could refer clients to the bank. In a memorandum to Baltimore trust and private banking personnel, Pettit described the task of planning the reception as “a large commitment for us during an extremely busy time.” Indeed, Pettit wanted to “make sure” it was “one of the most successful events we have sponsored.”
Sometime between the October 29 note from Brown and the November 6 reception assignment from Pettit, Runnebaum and Pet-tit had a meeting at which Pettit reduced (for the remainder of 1992) Runnebaum’s load of calls on “prospects” (potential clients) and “external referral sources.” Petit also mentioned “that there was a lot of jocular behavior going on” in staff meetings, “and she asked [Runnebaum] [ ] to [stop] partie-ipat[ing] in it.”
Runnebaum was diagnosed with HIV in 1988, but he was asymptomatic at all times relevant to this case. Runnebaum told Brown in September 1992 that he was infected with HIV, and Runnebaum asked if the bank’s employee health plan would pay for AIDS medication. Runnebaum asked Brown not to tell bank employees (except for those who administered the health plan) that he was infected. Brown said that he initially panicked when he learned that Runnebaum was HIV-positive.
In November 1992 Runnebaum placed his first order for the prescription drug azidoth-ymidine (AZT), and the bank health plan paid for the drug. AZT is well known to be one method of treating HIV infection and AIDS. Because Runnebaum could not wait at home to receive shipments of the drug, he had them delivered to the bank. Packages containing AZT (and addressed to Runneb-aum) were twice inadvertently opened by bank personnel.
On December 9,1992, Pettit sent Runneb-aum a handwritten note reading, “William— *1289I’m thrilled that you’re a part of our group. I look forward to seeing you shine.” On December 15, 1992, Runnebaum hosted the bank’s holiday reception. He brought his gay lover to the reception and introduced him to Pettit as his “boyfriend.”
Five days later, Runnebaum made his third sale, this one involving nearly $2 million in assets. The day before Christmas, An-dersson made his only sale of the year, involving $275,000 in assets. At year’s end Runnebaum had brought in nearly $5 million in assets. Runnebaum’s sales brought in $21,900 in fees to the bank, and Andersson’s sales brought in $2,750. . Both fee totals fell below the $40,000 target outlined in the sales goal letters.
On January 12, 1993, Pettit summoned Runnebaum to a meeting with Phillip Caw-ley, NationsBank’s personnel manager for the Baltimore/Washington area. Pettit fired Runnebaum at that meeting. According to Runnebaum, being fired
came as a total surprise. I had no verbal warnings, no written warnings. I was called in and let go and told I would be paid through the end of the month. And it totally blindsided me.
According to Pettit, Runnebaum was fired for failing to complete the assignments listed in the July memorandum and for failing to present a professional image. Andersson was not fired, even though he brought in only one-eighteenth as much business to the bank as did Runnebaum. Pettit said ih her deposition that she learned in late November or early December that Runnebaum was infected with HIV, but by then she had already decided to fire him. She claims that Run-nebaum’s disease played no role in her decision to fire him.
Runnebaum promptly filed an administrative claim with the Equal Employment Opportunity Commission and received a right-to-sue letter. He then filed suit against Na-tionsBank in the United States District Court for the District of Maryland. After discovery the district court granted the bank’s motion for summary judgment on the ground that Runnebaum failed to establish a prima facie case under the ADA. The court held in the alternative that Runnebaum did not forecast enough evidence to prove that the bank’s asserted rationale for firing him was merely pretextual. The court also granted summary judgment to the bank on the ERISA claim, saving that it decided the ERISA issue “under the same analytical framework as [the] ADA claim.” Runneb-aum appeals, and we reverse and remand for trial.
II.
Title I of the ADA, 42 U.S.C. § 12112, prohibits discriminatory discharge of “a qualified individual with a disability because of the disability.” To prove a violation, a plaintiff must establish (1) that he has a disability, (2) that he is otherwise qualified for the employment, and (3) that he was fired solely on the basis of the disability. Doe v. University of Maryland Medical System Corp., 50 F.3d 1261, 1264-65 (4th Cir.1995).
A.
Under the ADA,
The term “disability” means, with respect to an individual—
(A) a physical or mental impairment that substantially limits one ór more of the major life activities of such individual;
(B) a record of such an impairment; or
(C) being regarded as having such an impairment.
42 U.S.C. § 12102(2). The EEOC defines the term “regarded as having [a disability]” to include persons who have “a physical or mental impairment that substantially limits major life activities only as a result of the attitudes of others toward such impairment.” 29 C.F.R. § 1630.2(a)(2) (emphasis supplied).
Several courts have held that asymptomatic HIV infection is a disability per se. E.g., Gates v. Rowland, 39 F.3d 1439, 1446 (9th Cir.1994); Abbott v. Bragdon, 912 F.Supp. 580, 585-86 (D.Me.1995); Doe v. Kohn Nast & Graf, P.C., 862 F.Supp. 1310, 1321 (E.D.Pa.1994); Support Ministries for Persons With AIDS, Inc. v. Village of Waterford, 808 F.Supp. 120, 132 (N.D.N.Y.1992); Cain v. Hyatt, 734 F.Supp. 671, 679 (E.D.Pa.1990); Benjamin R. v. Orkin Exterminating Co., 182 W.Va. 615, 390 S.E.2d 814, 818 *1290(1990). Several federal agencies have reached the same conclusion. E.g., 29 C.F.R. § 34.2 (Department of Labor); 28 C.F.R. § 35.104 (Department of Justice); 24 C.F.R. Ch. I, Subch. A, App. I (Department of Housing and Urban Development); 34 C.F.R. § 1200.103 (National Council on Disability); 7 C.F.R. § 15e.l03 (Department of Agriculture); 5 C.F.R. § 1636.103 (Federal Retirement Thrift Investment Board); 22 C.F.R. § 1701.103 (Institute of Peace); 45 C.F.R. § 2301.103 (Arctic Research Commission). We rejected this approach in Ennis v. National Ass’n of Business & Educational Radio, 53 F.3d 55, 59 (4th Cir.1995), where we concluded that §. 12102(2) “requires that a finding of disability be made on an [individualized] basis.” More particularly, we said “the statute [ ] contemplates case-by-case determinations of whether a given impairment substantially limits a major life activity, whether an individual has a record of such a substantially limiting impairment, or whether an individual is being perceived as having such a substantially limiting impairment.” Id. at 60.
Runnebaum, though asymptomatic, has forecast sufficient evidence here to qualify under 42 U.S.C. § 12102(2)(C), which protects those who are regarded as having a disability.2 Bank employees knew Runnebaum was HIV-positive and knew he was taking AZT to treat the condition. Upon learning of Runnebaum’s condition, a bank supervisor, Michael Brown, felt “panicky” and “uncontrolled” and believed death might be imminent for Runnebaum.3 This is enough to show at the summary judgment stage that the bank perceived Runnebaum as having an- impairment that substantially limits a major life activity.
B.
The bank does not contest the second Doe element, that Runnebaum was otherwise qualified for his employment, but argues that Runnebaum has not met his burden with respect to the third element, causation. When a plaintiff seeks to prove causation by means of circumstantial evidence, as Runneb-aum does here, the familiar McDonnell Douglas method is applied. See McDonnell Douglas Corp. v. Green, 411 U.S. 792, 93 S.Ct. 1817, 36 L.Ed.2d 668 (1973) (Title VII case); Ennis, 53 F.3d at 57-58 (ADA case; McDonnell Douglas applied). Runnebaum has come forward with no direct evidence that he was fired solely on the basis of his disability, but the circumstantial ease he has forecast is sufficient to avoid summary judgment.
1.
The plaintiff first must establish a prima facie case of discrimination. A prima facie case under the ADA is established if the plaintiff proves that he is in the class protected by the Act and: (1) he was fired or demoted when (2) performing his job at a level which met his employer’s legitimate expectations and (3) his discharge occurred under circumstances indicating “that it is more likely than not that the adverse employment action was the product of discrimination.” Ennis, 53 F.3d at 58. The plaintiff’s burden of establishing a prima facie ease is merely a threshold burden and “is not onerous.” Texas Dep’t of Community Af*1291fairs v. Burdine, 450 U.S. 248, 253, 101 S.Ct. 1089, 1094, 67 L.Ed.2d 207 (1981).
The bank argues that Runnebaum has not established a prima facie ease because he was not performing his job at a level meeting the bank’s legitimate expectations. We believe that Runnebaum has forecast sufficient evidence to permit a jury to find that he was indeed performing at an adequate level.
A performance review completed by the bank’s private banking department in March 1992, before Runnebaum transferred to the trust department, rated him on a scale of one to seven. Seven is the highest rating; one is the lowest. A “four” indicates that the employee “consistently meets job requirements.” In the six categories completed, Runnebaum received a five, four fours, and a single three. The review therefore showed that Runnebaum “consistently” met his job requirements in five out of six performance categories. Notwithstanding some criticism, the numerical evaluation was amply supported by narrative praise. In the “Sales/ Sales Management” category Kines said that Runnebaum was “very diligent at following through on several very trying situations. He maintains his composure as well as the bank’s position in difficult circumstances, which provides balance to negotiations.” In commenting on the areas of “Personnel Management” and “Leadership Skills,” Kines said that Runnebaum, as marketing coordinator, did “an admirable job” in developing “a unique and innovative marketing plan for 1991.... This was an unusual responsibility for a new [officer], but William has the personal skills and apparent confidence to do well in these activities.” Finally, Kines said that Runnebaum “has shown great resourcefulness during his tenure at [NationsBank].” Kines’ follow-up review (relied upon heavily by the dissent, see post at 1297-98 & 1304-OS) in May 1992 also indicates satisfactory performance overall. Again, despite some criticism, Kines continued to praise Runneb-aum for providing “us with a good, strong marketing plan. Coordination has been done tactfully and less heavy-handedly than in the past.” Kines said that Runnebaum had made strides in the area of interpersonal skills, “buil[ding] bridges with peers that have enhanced his credibility.”
It is, however, Kines’ other evaluation in May 1992, when Runnebaum applied for a transfer to the trust department, that shows he was meeting the bank’s expectations at that time. Runnebaum could only apply for a transfer if he was “performing at a satisfactory level or above in [his] current position.” Kines, as Runnebaum’s supervisor in private banking, recommended him for the sales position in trusts. Specifically, Kines told the trust department that Runnebaum had “good skills and is a valuable member of the PB [private banking] team.” In recommending Runnebaum for the new job, Kines thus certified that Runnebaum was doing his current job at a satisfactory level or above.
Runnebaum’s supervisors continued to praise him after he began working in the trust department. Brown, NationsBank’s senior trust officer in Baltimore, sent Run-nebaum a handwritten “note of thanks and congratulations” on October 29, 1992, for planning the bank’s reception for a major client referral source, a law firm. A jury could reasonably conclude on the basis of this note that bank officials valued Runnebaum’s ability to plan successful social events that helped develop and maintain good relationships with referral sources and made them feel confident about steering potential clients to the bank.
A little more than a month after the successful reception, Pettit, Runnebaum’s immediate supervisor, wrote that she was “thrilled” to have Runnebaum in her group and looked forward to seeing him “shine.” And, in apparent recognition of Runnebaum’s success with the prior event, Pettit assigned him the important job of planning the bank’s “Greater Baltimore Holiday Reception.” Four hundred of the bank’s most important clients, most desired potential clients, and most significant “centers of influence” for business referrals were invited. The bank spent more than $10,000 on the event, which was held at the Center Club of Baltimore. Pettit personally asked Runnebaum to plan all aspects of the event, and she testified that “any function you plan correctly for clients takes effort.” In a three-page memorandum *1292to bank managers, Pettit described the reception as “a large commitment for us at an extremely busy time.” To encourage other managers to get involved in the advance work, Pettit said that Runnebaum and she would put $1 million in “Sweat equity5’ into planning the event. Pettit’s goal, as she said in the memorandum, was to make the reception “one of the most successful events we have sponsored.” 4
Even with the time Runnebaum spent to ensure that the event was successful, he still outsold Andersson 18 to 1. Indeed, just a few days after the reception (which went well), Runnebaum made a $2 million sale. Andersson, on the other hand, had not yet brought in a single dollar in sales. Anders-son did not make his only sale of the year (for $275,000) until a few days later.
A jury could reasonably infer that Runneb-aum met the bank’s legitimate expectations.
2.
Once the prima facie case has been established, the employer must then advance some legitimate, nondiscriminatory reason for the adverse employment action.
The bank principally relies on a “Memo to Personnel File” (“the Pettit/Caw-ley memo”) dated January 7,1993, that Pettit drafted with the assistance of the personnel manager, Cawley.5 The Pettit/Cawley memo says that Runnebaum was fired primarily for (1) failing to complete all of the “training tasks” Pettit outlined in the July memorandum and (2) failing to present a professional image inside and outside the bank. These assertions constitute legitimate, nondiserimi-natory explanations for the bank’s action and satisfy the bank’s burden of production.6
3.
Even though the bank met its burden of production under step two of the McDonnell Douglas analysis, Runnebaum still has come forward at step three with sufficient evidence to survive summary judgment.
*1293To prevail ultimately at trial, Run-nebaum must prove (1) that the bank’s explanation is pretextual and (2) that the bank intentionally discriminated against him because of his disability. See St. Mary’s Honor Ctr. v. Hicks, 509 U.S. 502, 508-11, 113 S.Ct. 2742, 2748-49, 125 L.Ed.2d 407 (1993). When this final burden of persuasion is factored into the summary judgment analysis, it means that a plaintiff is required to forecast evidence showing a genuine issue of material fact on the ultimate question of pretext and discrimination. Mitchell v. Data General Corp., 12 F.3d 1310, 1316 (4th Cir.1993); see also Tomka v. Seiler Corp., 66 F.3d 1295, 1308-10 (2d Cir.1995); Collier v. Budd Co., 66 F.3d 886, 892 (7th Cir.1995); Waldron v. SL Indus., Inc., 56 F.3d 491, 492-93 (3d Cir.1995); Torre v. Casio, Inc., 42 F.3d 825, 829-30 (3d Cir.1994); Durham v. Xerox Corp., 18 F.3d 836, 839-40 (10th Cir.), cert. denied, — U.S. -, 115 S.Ct. 80, 130 L.Ed.2d 33 (1994); Washington v. Garrett, 10 F.3d 1421, 1433 (9th Cir.1994); Hairston v. Gainesville Sun Publishing Co., 9 F.3d 913, 921 (11th Cir.1994); Developments in the Law — Employment Discrimination, 109 Harv. L.Rev. 1568, 1599-1601 (1996).
Because an employer’s true motive for firing an employee may be difficult to determine, and because the facts indicating that motive vary widely from case to case, a plaintiff is not required to show pretext and discrimination by any particular kind of evidence at the summary judgment stage, so long as there is some evidence in the summary judgment record showing that he could prevail at trial. Patterson v. McLean Credit Union, 491 U.S. 164, 187-88, 109 S.Ct. 2363, 2378-79, 105 L.Ed.2d 132 (1989). Runneb-aum has met his burden, and the district court erred in granting the bank summary judgment.
Runnebaum could rely on the following facts to convince a rational trier of fact that the bank’s asserted justifications are pretex-tual and that Runnebaum was discriminated against because he was regarded as having a disability. We do not hold that any one fact alone would preclude summary judgment. Taken together, however, they demonstrate the existence of a genuine issue of material fact on the ultimate question of pretext and discrimination.
a.
Runnebaum’s and the bank’s respective versions' of the facts leading up to his discharge are in stark contrast. Runnebaum has forecast specific evidence that would allow a reasonable finder of fact to disbelieve the bank’s version of events and to find the bank’s witnesses not credible.
The factfinder’s disbelief of the reasons put forward by the defendant (particularly if disbelief is accompanied by a suspicion of mendacity) may, together with the elements of the prima facie case, suffice to show intentional discrimination. Thus, rejection of the defendant’s proffered reasons, will permit the trier of fact to infer the ultimate fact of intentional discrimination.
St. Mary’s Honor Ctr., 509 U.S. at 511, 113 S.Ct. at 2749 (emphasis in original).
The main charge against Runnebaum in the Pettit/Cawley memo is that he failed to attend a sufficient number of “prospect” sales calls. According to the dissent, see post at 1303-04, this shows Runnebaum’s “utter failure to attend to his assigned duties.” But a careful look at the summary judgment record belies this claim. When the record is viewed in the light most favorable to Run-nebaum, it is evident that Pettit denied him prospect call credit he should have been granted. Runnebaum was denied credit for all nine such calls he made with Brown on the ground that Brown was not officially a sales officer, even though Pettit admitted that Brown was “expected to be interested in sales” as the trust department’s Baltimore city manager. Runnebaum also was denied credit for a prospect call he made with Sara Tapiero, a portfolio manager, and for eight calls he made alone. Ironically, Runneb-aum was not given any sales call credit for the three calls he made that resulted in actual sales. Andersson, by contrast, who was not HIV-positive and who was not fired, was given credit for calls he made with Brown and Tapiero, as well as for four calls he made alone.
*1294The PettiVCawley memo also charges Runnebaum with failing to make a sufficient number of “external referral source” calls, meetings with people (such as lawyers and accountants) who could potentially refer business to the bank. Runnebaum made twelve external referral source calls. But again, Runnebaum was denied credit for nine of ten such calls he made with Brown and for one call he made alone.
Runnebaum also creates a factual dispute about the legitimacy of other reasons assigned for his discharge in the PettiVCawley memo. For example, he was faulted for attending no Baltimore Estate Planning Council meetings. However, Runnebaum joined the council (along with Brown), but no meetings were scheduled between the time he joined and the time he was fired. Similarly, Runnebaum was faulted for failing to send Pettit blind carbon copies of his correspondence. But all correspondence on Runneb-aum’s matters went' out over Brown’s signature, and Runnebaum “feel[s] certain” he told Pettit about this arrangement.
Another contention of the bank is that Runnebaum did not always make a timely submission of activity and call reports to Pettit. Andersson, however, had the same deficiency. According to Pettit, “both of them had slacked off.” Although she put nothing in either’s personnel file, Pettit counseled both men. The conduct of both men in the reporting area then improved. Nevertheless, this earlier shortcoming was used as a reason to fire Runnebaum, while Anders-son, who had the same “failure to attend to his assigned duties,” see post at 1308-04, was not fired.
In response to the charge that he failed to present a professional image, Runnebaum contends that the bank now overstates the significance of the incidents cited. Runneb-aum’s joking around, for example, seems to have been common behavior for many members of the Baltimore office. According to Runnebaum, internal meetings “got out of hand from time to time with all members of the sales staff,” primarily because the bank’s salespeople were “highly energized” and proné to “a lot of horseplay.” Similarly, Pettit wrote off the “inappropriate behavior” Runnebaum allegedly engaged in at a presentation to a law firm shortly after joining the trust department, see post at 1298-99, to his inexperience. According to Brown, Pettit simply said “he is young,” and “he has got to learn it is okay not to say anything.” Moreover, the bank has not explained why Run-nebaum was allowed (near the end of his tenure) to be co-host with Pettit of the holiday reception, to which 400 clients, potential clients, and “referral sources” were invited, if his behavior could not be trusted. Thus, Runnebaum claims that his behavior did not seriously trouble the bank until it learned he was infected with HIV and needed an after-the-fact rationalization to fire him.
The PettiVCawley memo’s questionable reliability, then, weighs against summary judgment. Runnebaum’s evidence, if believed at trial, supports reasonable “disbelief of the reasons put forward by the defendant” and “rejection of the defendant’s proffered reasons,” which would permit a reasonable finder of fact to “infer the ultimate fact of intentional discrimination.” St. Mary’s Honor Ctr., 509 U.S. at 511, 113 S.Ct. at 2749.
b.
The timing of Runnebaum’s termination also raises a sufficient question of pretext and discrimination to weigh against summary judgment. See EEOC v. Ackerman, Hood & McQueen, Inc., 956 F.2d 944, 949 (10th Cir.), cert. denied, 506 U.S. 817, 113 S.Ct. 60, 121 L.Ed.2d 28 (1992). Runnebaum was given additional marketing responsibilities relatively early in his tenure with the trust department, and he even received a note of praise from his supervisor, Pettit. Just a short time later, though, Runnebaum was fired. The record thus presents an unresolved material question: what caused the bank’s attitude toward Runnebaum to change so suddenly.
Runnebaum argues that the change came with Pettit’s discovery that Runnebaum was HIV-positive or with her learning that he was receiving medication to treat his condition. The bank claims, however, that Pettit had already made the decision to fire Run-nebaum before she learned of his disability and that the bank employees who opened *1295Runnebaum’s medicine packages never told Pettit that Runnebaum was taking AZT. Whether Pettit resolved to fire Runnebaum before or after she learned he was HIV-positive and whether she knew Runnebaum was taking AZT, however, are questions of fact that must be resolved at trial. More particularly, these questions center on Pet-tit’s credibility, and questions of witness credibility must be left to the trier of fact. Tuck v. Henkel Corp., 973 F.2d 371, 376 (4th Cir.1992), cert. denied, 507 U.S. 918, 113 S.Ct. 1276, 122 L.Ed.2d 671 (1993); see also Beardsley v. Webb, 30 F.3d 524, 530 (4th Cir.1994); Gray v. Spillman, 925 F.2d 90, 95 (4th Cir.1991).
Pettit’s inconsistent behavior supports a finding of discriminatory intent. Pettit claims she decided to fire Runnebaum sometime in November 1992, but she never warned him that he was in danger of losing his job. Furthermore, on December 9 she praised him, sending him a handwritten note reading, “William — I’m thrilled that you’re a part of our group. I look forward to seeing you shine.” This cuts against the bank because bosses generally do not praise employees they have decided to sack. Pettit’s conduct sheds doubt on her claim that she resolved to fire Runnebaum before she learned he was infected with HIV.7
Finally, we mention again that Pettit trusted Runnebaum to plan and host the most important bank social event of the year. Would a reasonable bank official budget'$10,-000 for her most important marketing event of the year, only to entrust the event’s planning and execution to a person who posed a risk of alienating those who would attend? The answer is obvious and suggests that a reasonable finder of fact could disbelieve the bank’s asserted rationale for terminating Runnebaum.
From the foregoing, a jury could find that Pettit decided to fire Runnebaum after she sent him the December 9 note and soon after she learned that he was HIV-positive. This finding would support Runnebaum’s claim that the bank discriminated against him solely because he was infected with the AIDS virus.
c.
Brown’s reaction upon learning that Run-nebaum was infected with HIV could also lend support for a finding of pretext and discrimination.
Many disabilities are apparent to a casual observer. An employer can see a wheelchair, a guide dog, or a hearing aid. Other disabilities, however, are invisible to the naked eye. Runnebaum’s alleged disability, being HIV-positive, falls into the latter category. When a disability is not readily apparent, an employer’s reaction upon learning of the disability can be relevant to a finding of discrimination. Specifically, an employer’s immediate reaction often can provide insight into his motives for later firing a disabled employee.8
*1296When Brown learned that Runnebaum was HIV-positive, he immediately felt
panic, panic because I was thinking how am I going to work, you know, and be a friend to somebody who is HIV positive. I’ve educated myself a lot since then. But, you know, suppose he dies on me. Should I tell Ann[PettitJ at this point, should I tell the bank? I remember feeling panicky, uncontrolled.
(Emphasis supplied.)
The finder of fact could view this statement as evidence that Pettit learned from Brown that Runnebaum was HIV-positive before she decided to fire him. This evidence also lends support for a finding that Runnebaum was not fired because of poor performance, but because supervisors at the bank panicked at the thought of having an AIDS patient on the payroll.9
d.
Runnebaum has also come forward with comparative evidence in support of his claim of pretext. “Comparative evidence is that which shows employees who were not members of the protected class were treated differently.” Reeves v. Thigpen, 879 F.Supp. 1153, 1176 (M.D.Ala.1995). A plaintiff may use comparative evidence to show the existence of a genuine issue of material fact on the question of pretext and thereby defeat a defense summary judgment motion. Id. at 1175-76; see also Alvarado v. Bd. of Trustees of Montgomery Community College, 928 F.2d 118, 122 (4th Cir.1991) (affirming judgment, after bench trial, on basis of comparative evidence).
Runnebaum outsold Andersson (who was not regarded as having a disability) by a factor of 18 ($5 million to $275,000), but Andersson was not fired even though An-dersson and Runnebaum were hired at the same time and were given identical sales goals. Brown testified that the key goal of salesmen like Runnebaum and Andersson was “to bring in new business.” In addition, another bank employee, David Kutch, said that Runnebaum, like Andersson, was “there to produce volume.” Finally, the record does not disclose that Andersson spent large amounts of time (as did Runnebaum) organizing important marketing events at the bank’s request. We recognize that Runneb-aum may have had shortcomings, as the bank claims, justifying his firing. But given the bank’s overriding emphasis on sales, a question is raised when the salesman who was fired brought in 18 times as much business as the salesman who was not fired. Moreover, as we discussed above, Pettit was much more lenient with Andersson on granting credit for sales calls and on excusing his tardiness in turning in activity and call reports. A jury could reasonably see these inconsistencies as evidence of pretext and discrimination.10
III.
The dissent’s criticisms largely boil down to a factual attack. And while the dissent does a good job of arguing that the facts may reasonably be read in the bank’s favor, that argument is not enough to establish the bank’s right to summary judgment. Although a factfinder could reasonably choose to believe the bank, the same factfinder could also reasonably determine on the basis of the *1297record before us that the bank’s explanation for firing Runnebaum is not worthy of ere-dence and that discrimination was the true motivation for his termination.
In sum, Runnebaum has forecast evidence of all the elements of a prima facie case and evidence to support a finding of pretext and discrimination. Runnebaum’s ADA claim must survive summary judgment because there is a genuine issue of material fact as to whether he was fired because he was regarded as having a disability.11 We reverse and remand for trial.
REVERSED AND REMANDED.
. Pettit, of course, was Runnebaum's supervisor. Pettit’s office, however, was in Tyson's Comer, Virginia, so Runnebaum worked closely with Brown, whose primary responsibility was to "take care of” existing trust business in the Baltimore office.
. The dissent says that it is significant and important, see. post at 1298 & 1302, that Runneb-aum checked a box indicating that he was not handicapped when he applied for the job in the trust department. This overlooks the fact that the attitudes of others determine whether a person has a disability within the meaning of subsection (C). Moreover, it is settled that an employee may not prospectively waive his right to be protected under the ADA. Alexander v. Gardner-Denver Co., 415 U.S. 36, 51, 94 S.Ct. 1011, 1021, 39 L.Ed.2d 147 (1974); Riley v. Weyerhaeuser Paper Co., 898 F.Supp. 324, 326 (W.D.N.C.1995), appeal dismissed in part, aff'd. in part, 77 F.3d 470 (4th Cir.1996) (table); H. Rep. No. 485(III), 101st Cong., 2d Sess. 76-77 (1990), reprinted in 1990 U.S.C.C.A.N. 445, 499-500.
. The dissent, examining other statements Brown made, says that Brown simply viewed himself as Runnebaum’s 'protector,” which (the dissent argues) does not show that Brown regarded Run-nebaum as having a disability. See posted. 1302. This analysis, however, begs the question. If Brown did not regard Runnebaum as having a disability, why did he regard Runnebaum as needing his protection? Brown’s reaction shows his firm belief that bank officials and employees would respond negatively to the news that Run-nebaum was infected.
. Although the dissent tries to belittle Runneb-aum by saying that he got too involved in the "minutiae'' and "inconsequentia'' of the reception, see post at 1303 & 1299-1300, it was Pettit herself, in her memorandum to bank managers, who emphasized the importance of seeing to every last detail. To dismiss Runnebaum's attention to detail as "squandered” time is to misread completely what Pettit expected of him on this project. Indeed, even if Pettit had not been so detailed in her instructions, it would have been irresponsible of Runnebaum to oversee a $10,000 marketing event and not to pay close attention to the particulars of making it successful.
. The dissent relies heavily on Runnebaum's behavior when he worked in the private banking department. See post at 1297-98. The Pet-til/Cawley memo does not suggest that Runneb-aum's performance in private banking justifies his discharge from his job in the trust department. The dissent puts far too much weight on negative events that occurred early in Runneb-aum's tenure in private banking, even though those events are, by the dissent's later admission, "too temporally remote” to be taken seriously. See id. at 1304. As we have said, according to the bank’s own policy, Runnebaum could not have been hired by the trust department if his performance in private banking was not "at a satisfactory level or above.” Runnebaum's private banking supervisor, Michael Kines, was on the whole pleased with Runnebaum’s performance. Although Kines recognized that Runneb-aum was not without weaknesses, he noted that Runnebaum "has shown a willingness to lake action and develop in the right direction.” Considering everything, Kines believed that Runneb-aum's strengths justified his promotion to trusts.
The dissent also faults Runnebaum for spending “a great deal of time to advancing his acting career.” See post at 1300. The record reveals that most of Runnebaum's efforts in the acting arena took place while he worked in private banking and that his boss (Kines) encouraged those efforts. Kines viewed Runnebaum’s theatrical work as a creative way to get involved in the community, to improve the bank’s image, and to develop contacts with potential clients. Kines, for example, encouraged the entire private banking staff to attend Runnebaum’s performance as Tom load in Grapes of Wrath. Indeed, Runnebaum testified that "numerous clients” attended his performances and that he got business referrals as a result of his avocation as an actor. Finally, Kines himself occasionally sang opera and was a member of various church choirs and the opera guild. At no time did anyone at the bank tell Runnebaum that his extracurricular activities were unacceptable; indeed, it appears that those activities were encouraged.
.As we discuss below, however, Runnebaum offers specific evidence to challenge the credibility of the bank's asserted rationale for terminating him and to demonstrate that the justification asserted was merely a pretext for discrimination.
. The dissent, see post at 1305, fails to recognize the importance timing plays in this case. The dissent says that the December 9 note "is cast in anticipation of future achievements,” "speaks in terms of future hope,” and "merely ... hop[es] for a profitable future" for Runnebaum. Id. (emphasis in original). Pettit claims, however, that she sent the note a month after she had “resolved conclusively to discharge Runnebaum.” Id. at 1299. The dissent fails to explain this glaring inconsistency between Pettit’s purported intent and her undisputed conduct. If Pettit had conclusively resolved to fire Runnebaum before she sent the note, what “profitable future” did she foresee for him? The finder of fact could conclude that Pettit’s claim that she resolved to fire Runnebaum before she learned he was infected with HIV lacks the ring of truth. Thus, the question of Pettit’s credibility is squarely in issue and militates against summary judgment. See St. Mary’s Honor Ctr., 509 U.S. at 510-11, 113 S.Ct. at 2749; Mitchell, 12 F.3d at 1316.
. Our analysis of this issue is guided by cases interpreting the Pregnancy Discrimination Act of 1978. See Lempres v. CBS Inc., 916 F.Supp. 15, 23 n. 37 (D.D.C.1996) (Pregnancy Discrimination Act plaintiff must meet requirements similar to those imposed on ADA plaintiffs). Pregnancy is not observable at first. Yet an employer’s reaction upon learning that an employee is pregnant can be relevant in proving that he later fired her with discriminatory intent. EEOC v. Ackerman, Hood & McQueen, Inc., 758 F.Supp. 1440, 1453 (W.D.Okla.1991), aff'd, 956 F.2d 949 (10th Cir.), cert. denied, 506 U.S. 817, 113 S.Ct. 60, 121 L.Ed.2d 28 (1992); accord Metz v. Merrill Lynch, Pierce, Fenner & Smith, Inc., 39 F.3d 1482, 1485 & 1491-92 (10th Cir.1994); Thompson v. La Petite Academy, Inc., 838 F.Supp. 1474, 1477-78 (D.Kan.1993); cf. McDonnell Douglas, 411 U.S. *1296at 804, 93 S.Ct. at 1824 (employer's “reaction, if any” upon learning of plaintiff's civil rights activities is relevant to show pretext).
. Improperly reading Brown's statement in the light most favorable to the bank, the dissent claims that it proves Brown’s lack of discriminatory motive toward Runnebaum and that Brown’s motive always was to be Runnebaum’s “protector.” See post at 1307. Yet Brown admitted in his deposition that there was occasionally bad blood between him and Runnebaum, that sometimes their discussions had been "combative or argumentative," and that Runnebaum believed Brown had a "vendetta" against him. Because on summary judgment all facts and reasonable inferences must be construed in the light most favorable to the non-moving party, the finder of fact must be allowed to determine at trial the true nature of the relationship between Run-nebaum and Brown.
. The bank currently employs other HIV-infected persons. The bank may not, however, be granted summary judgment simply because it has a few employees within the protected class. See O’Connor v. Consolidated Coin Caterers Corp., — U.S. -, 116 S.Ct. 1307, 134 L.Ed.2d 433 (1996); Carson v. Bethlehem Steel Corp., 82 F.3d 157, 158-59 (7th Cir.1996).
. Because the district court granted summary judgment on Runnebaum’s ERISA claim for precisely the same reasons summary judgment was granted on the ADA claim, and because the relevant elements of the prima facie case are the same, see Conkwright v. Westinghouse Elec. Corp., 933 F.2d 231, 239 (4th Cir.1991), Runnebaum’s ERISA claim must survive as well.