Plaintiffs-appellees (plaintiffs) seek to maintain this action on behalf of certain present and former stockholders of Oppenheimer Fund, Inc. (the Fund), an investment company registered under the Investment Company Act of 1940, 15 U.S.C. § 80a-l et seq. This is an appeal under 28 U.S.C. § 1291 from an interlocutory order holding the suit to be properly maintainable as a class action under Rule 23(b)(3), Fed.R. Civ.P., and directing the defendant-appellant (defendant) Fund to bear substantial costs in identifying the names and addresses of the class members so that plaintiffs can send them the initial notice of the pending action as required by Rule 23(c)(2), Fed. R. Civ.P.
When the motion for class determination was made, there were over 67 million shares of the Fund outstanding held by approximately 173,000 shareholders. Of the approximately 121,000 present or former shareholders who constitute the class designated by the plaintiffs, about 103,000 remain shareholders and 18,000 have sold their shares. The information needed by plaintiffs for the preparation of the notice to the members of the class, particularly the names and addresses of the class members, is contained in magnetic computer tapes kept by the transfer agent of the Fund. The extraction of this information from the tapes would require, in addition to the usual processing, the design of new computer programs. The cost of accomplishing this task was estimated by the transfer agent to be $16,580 as of October 10, 1973.
On. each of the issues presented, identification costs and designation as a manageable class action, we must first decide if the issue is reviewable on appeal and, if so, then determine if the district court’s decision should be upheld. Since we find that our treatment of the identification costs matter affects the designation question, we discuss the identification costs matter first.
The Allocation of Identification Costs
The order requiring the Fund to bear the identification costs is appealable because it fits squarely within the collateral order doctrine of Cohen v. Beneficial Loan Corp., 337 U.S. 541, 69 S.Ct. 1221, 93 L.Ed. 1528 (1949). The requirements of that doctrine are essentially twofold: first, the decision appealed from must not be “tentative, informal or incomplete,” 337 U.S. at 546, 69 S.Ct. 1221, but rather it must conclusively settle a party’s, claim; second, the decision must involve a collateral matter that can be reviewed apart from the merits of the case but which cannot be effectively reviewed on appeal from the final judgment. In Eisen v. Carlisle & Jacquelin (Ei-*639sen IV), 417 U.S. 156, 94 S.Ct. 2140, 40 L.Ed.2d 732 (1974), the Supreme Court faced the question whether this court had jurisdiction in Eisen v. Carlisle & Jacquelin (Eisen III), 479 F.2d 1005 (2d Cir. 1973) when we reviewed the district court’s order imposing notice costs on the defendants. The Supreme Court decided that the order was appealable because it was “ ‘a final disposition of a claimed right which is not an ingredient of the cause of action and does not require consideration with it.’ ” 417 U.S. at 172, 94 S.Ct. 2150, quoting Cohen, supra, 337 U.S. at 546-47, 69 S.Ct. 1221. See also, General Motors Corp. v. City of New York, 501 F.2d 639, 647 (2d Cir. 1974). We find this question of appealability controlled by Eisen IV.
We turn next to the merits of the order allocating identification costs. Rule 23(c)(2), Fed.R.Civ.P., provides in relevant part:
In any class action maintained under subdivision (b)(3), the court shall direct to the members of the class the best notice practicable under the circumstances, including individual notice to all members who can be identified through reasonable effort.
Since this is a class action brought under subdivision (b)(3) of the rule, namely, one in which the court below found that the questions of law or fact common to the members of the class predominate over any questions affecting only the individual members, and that the class action was superior to other available methods, individual notice of the action must be sent to all class members who can be identified by name and address through a reasonable effort. Eisen IV, 417 U.S. at 173-77, 94 S.Ct. 2140. The cost of such notice must be borne in the first instance by plaintiff. Id. 417 U.S. at 177-79, 94 S.Ct. 2140; Eisen III, 479 F.2d 1005, 1009 (2d Cir. 1973); Eisen II, 391 F.2d 555, 568 (2d Cir. 1968). The authorities just cited enunciate the views of the Supreme Court and this court that, absent special circumstances, if the plaintiff does not accept this expense, the class action cannot be maintained. In the usual case, defendants may not be compelled to provide financial support for a class action against themselves.
Where, as here, the relationship between the parties is truly adversary, the plaintiff must pay for the cost of notice as a part of the ordinary burden of financing his own suit.
Eisen IV, 417 U.S. at 178-79, 94 S.Ct. at 2153.
The possibility that plaintiff may not be required to defray the cost of notice is still an open question in some cases. The Supreme Court declined to foreclose the possibility in “situations where a fiduciary duty pre-existed between the plaintiff and defendant, as in a shareholder derivative suit.” Eisen IV, supra, 417 U.S. at 178, 94 S.Ct. at 2153. In addition to the derivative suit, we have suggested that there may be other similar eases in which justification might be found for holding that a representative plaintiff is not obligated to defray the cost of notice, citing “a case where a public utility corporation which regularly sends monthly bills to its current customers has been held to have overcharged its customers and the class suit is brought to compel a refund.” Eisen III, 479 F.2d 1005, 1009 n. 5 (2d Cir. 1973). The district judge does not appear to have pursued this line of analysis and the plaintiffs have mentioned it only in passing.
Assuming that there may be cases where the imposition of notification costs on the defendant may be justified, we do not think this is such a case. The defendant Fund is not a public service monopoly with the responsibilities incumbent upon such an entity, and no finding of liability has yet been entered against it. The Supreme Court in Eisen IV did not attempt to elucidate the exceptional case in which a representative plaintiff might be relieved of this burden. Indeed, it did not unequivocally state that there was such a case. It did speak of the shareholder derivative suit but that.apparently was by way of analogy since the derivative suit is not a class action, though *640possibly akin thereto.1 The Supreme Court also described Eisen IV as a case where “the relationship between the parties is truly adversary.” 417 U.S. at 178, 94 S.Ct. at 2153. Possibly this was intended to contrast it with a derivative suit where the corporation, though a nominal defendant, has interests closely aligned with the plaintiff and indeed would be the beneficiary of any recovery. The equities in favor of imposing some costs on the corporation in that situation are obvious. But the Supreme Court more likely had in mind an arms-length relationship unencumbered by fiduciary duties. The relationship between the plaintiffs and the Fund is probably not “truly adversary” in the Eisen IV sense. Although the Fund is not in the position of the corporation in a derivative suit,2 we may assume it had fiduciary duties to the purchases of its shares. See Dolgow v. Anderson, 43 F.R.D. 472, 498-99 (E.D.N.Y. 1968). But the relationship between the plaintiffs and the Fund is not non-adversarial in a manner which requires an exception to the Eisen IV rule on notification costs, but in a manner that makes it totally improper to impose costs on the Fund: the Fund is not a party to the class action claims.3 No recovery is sought from the Fund in the class action. The plaintiffs have been careful to exclude the Fund itself from all allegations of wrong-doing and to seek recovery only from its directors, its managing company and the broker-dealer firm that controls the manager. Indeed, the Fund appears to have been named as a defendant only for purposes of the derivative claims which are not of concern here. Since the Fund has no direct interest in the outcome of the class action claim, it is too remotely involved to have notification costs imposed upon it.
Furthermore, we do not think these costs could properly be imposed on the other defendants. Even if we assume that these defendants — the directors of the Fund, its manager, and the firm that controlled the manager — had fiduciary duties to the plaintiff shareholders, that would be insufficient in our opinion to warrant imposition of notification costs on them on the facts of this case. Many of the considerations pointed to in justification for shifting the costs, see Dolgow v. Anderson, supra, 43 F.R.D. at 498-500; Eisen v. Carlisle & Jacquelin, 52 F.R.D. 253, 264-70 (S.D.N.Y. 1971), have been shown to be inappropriate. The district court may not weigh the merits and cite the strength of a plaintiff’s case as justification.4 The result in Eisen IVleaves no doubt that the ability of a defendant to bear the costs and the fact that, if it does not, the suit will have to be discontinued, are to be given little or no weight. The public interest in enabling the adjudication *641of claims that could not be maintained in any other form and in having remedial statutes enforced is sharply offset by the danger, all too frequently realized, of large settlements paid irrespective of the merits of the claim in order to avoid the disastrous expenses of litigation. Eisen III, supra, 479 F.2d at 1019. Even the contention that the defendant has an interest in obtaining the effects of res judicata against all members of the class often rings untrue. If the class action proceeds, the defendant may pay large sums in defending claims that might not otherwise have been brought due to the limited interest of the individual plaintiffs.5 In sum, we perceive no special circumstances in this case that would warrant shifting the costs of notification from the plaintiffs to any of the defendants. We have suggested before that the vindication of valid class claims not maintainable under Rule 23(b)(3) or otherwise is a matter for Congress. Eisen III, 479 F.2d at 1019.
The justification that the District court found for imposing some costs on the defendant Fund was twofold. First, it found the expense was “relatively modest,” apparently in relation to the assets of the Fund which exceeded $500,000,000. This is an inappropriate consideration in the determination of the incidence of notice costs, even if the costs force the plaintiffs to discontinue as in Eisen IV. The second reason given was that “it is defendants who are seeking to have the class defined in a manner which appears to require the additional expense.” This bears some analysis. Plaintiffs defined the class as all persons who purchased shares of the Fund during the period March 28,1968 to April 24,1970. Discovery then revealed that this class consisted of approximately 121,000 persons, 103,000 of whom were still Fund shareholders, and that the cost of the required computer operations to extract the names and addresses of the class members from the lists of past and present Fund shareholders would be approximately $16,580. Plaintiffs then sought to redefine the class to exclude the 18,000 persons included in the original class who no longer hold Fund shares, and to send the required notice by inserting it in a regular mailing to all present Fund shareholders. The defendants objected to the exclusion of the 18,000 persons, presumably because it would limit the res judicata effect of the suit. The district court reached the same conclusion but for a different reason, holding that these persons could not be excluded because to do so “would involve an arbitrary reduction in the class.”6 The class as originally defined was found to constitute the proper class for reasons unrelated to the interests of the defendants. It would thus be inconsistent to say that it is a proper class only if the defendants pay the costs. The two issues are distinct.
The defendants also opposed sending the notice to the 68,000 shareholders who are not class members, expressing concern that such a mailing could lower investor confidence and trigger a wave of redemptions. The district court did not pass on the validity of this concern; it merely noted that the concern was obviated by having the defendant cull the non-members from the lists. However, there is evidence in the record to substantiate the concern. Plaintiffs assert that the Fund shareholders have been advised of the nature and pendency of this suit 13 times since 1970 in proxies, prospectuses and annual reports. But we think that notice of that type — usually several paragraph^ in a footnote written by management and with a strong denial of merit — would have a far milder impact than a separate communication (though mailed with other papers) composed by the plaintiffs, giving a detailed explanation of the claims and without a denial of merit, particularly when the latter portends the immi*642nent prosecution of a matter which the steady flow of prior notices had indicated was dormant if not defunct. In these circumstances, we think that the defendants concern was legitimate and the district court could not properly condition its abatement on defendants’ shouldering of the notice costs. The identification costs cannot be viewed as additional expense necessitated by unreasonable or partisan demands on the part of the defendants.
Plaintiffs attempt to distinguish Eisen III and Eisen IV by asserting that the cost of identifying the members of a class is not a part of notifying those members. They further suggest that identification costs are akin to the expense borne in discovery which a district judge may in his discretion require a party to bear unless the party can show that it is unreasonable and oppressive, citing, inter alia, 8 C. Wright & A. Miller, Federal Practice and Procedure, § 2218 at 659 (1970), and 4A J. Moore, Moore’s Federal Practice H 33.20 (2d ed. 1975). However, we are of the opinion that the cost of obtaining the name and address to be affixed to the envelope does not differ in kind from the cost of printing the notice and of procuring, stuffing and posting the envelopes. Moreover, if the rules of discovery were applicable, it appears unlikely that they would require that defendants bear the identification costs here. Rule 33(c), Fed.R.Civ.P., designed to protect parties from burdensome interrogatories, provides:
(c) Option to Produce Business Records. Where the answer to an interrogatory may be derived or ascertained from the business records of the party upon whom the interrogatory has been served or from an examination, audit or inspection of such business records, or from a compilation, abstract or summary based thereon, and the burden of deriving or ascertaining the answer is substantially the same for the party serving the interrogatory as for the party served, it is a sufficient answer to such interrogatory to specify the records from which the answer may be derived or ascertained and to afford to the party serving the interrogatory reasonable opportunity to examine, audit or inspect such records and to make copies, compilations, abstracts or summaries.
Under this rule, a party will not be required to perform burdensome extraction of information from sources that are available to the party seeking discovery. See 4A J. Moore, Moore’s Federal Practice 1133.20 at 33-103 (2d ed. 1975); Tytel v. Richardson-Merrell, Inc., 37 F.R.D. 351 (S.D.N.Y.1965); Konczakowski v. Paramount Pictures, Inc., 20 F.R.D. 588 (S.D.N.Y.1957). If the discoverer should proceed under one of the other rules governing discovery, the respondent could obtain a protective order under Rule 26(c) from “undue burden or expense.” Nevertheless, we do not rely on this point since we find the discovery rules inapplicable.7
The Class Action Designation
We turn next to the designation of the suit as a class action. The determination of the district court that the action met *643the requirements of Rule 23(b)(3) was discretionary. It is not appealable under the collateral order doctrine. In seeking to arrive at some standards by which to determine the appealability of such an order, we have developed a three-pronged test as set forth in Herbst v. International Telephone & Telegraph Corp., 495 F.2d 1308, 1312 (2d Cir. 1974), and refined in Kohn v. Royall, Koegel & Wells, 496 F.2d 1094 (2d Cir. 1974) , General Motors Corp. v. City of New York, 501 F.2d 639 (2d Cir. 1974), in Parkinson v. April Industries, Inc., 520 F.2d 650 (2d Cir. 1975) and, most recently, in In re Master Key Antitrust Litigation, 528 F.2d 5, 10-13 (2d Cir. 1975). See also Handwerger v. Ginsberg, 519 F.2d 1339 (2d Cir. 1975) . In Parkinson, we recognized the “renewed emphasis on the policies of finality” and indicated that only in “extraordinary circumstances” would exceptions to the final judgment rule be permitted. 520 F.2d at 657-58. Although it may be a close question whether that three-prong test is satisfied here, we do not decide that question. We think we may properly review the class action designation because the order in which it was made is properly before us on another ground. Judge Friendly, in his concurrence in Parkinson, supra, 520 F.2d at 660, suggested that this exception should be made even if appeals from the grant or denial of class action designation are allowed only under the certification procedures of 28 U.S.C. § 1292(b). There is sufficient overlap in the factors relevant to both issues to warrant our exercising plenary authority over this appeal. Eisen IV, supra, 417 U.S. at 172; Hurwitz v. Directors Guild of America, Inc., 364 F.2d 67 (2d Cir.), cert. denied, 385 U.S. 971, 87 S.Ct. 508, 17 L.Ed.2d 435 (1966). See San Filippo v. United Bhd. of Carpenters & Joiners, 525 F.2d 508 (2d Cir. 1975); General Motors Corp. v. City of New York, 501 F.2d 639, 648 (2d Cir. 1974); 9 J. Moore, Moore’s Federal Practice ¶ 110.25[1], at 272-73 (2d ed. 1975).
Turning to the merits of the class action designation we find that the granting of class action status was proper. As Judge Griesa found, the requisite numer-ousness is present and common questions of law and fact predominate over any questions affecting only the individual members of the class. Moreover, we cannot, at this stage of the litigation, support defendants’ claim of unmanageability. They contend that proof of liability and damages “may well involve millions of individual computations,” and that the aggregate damages sustained by the class may not be as great as plaintiffs claim. Nevertheless, the district judge is in the best position to make a determination of manageability and has considerable discretion in doing so. Modern computer technology can bring formerly insurmountable tasks within the range of manageability. If, on the other hand, unmanageability should develop or facts should arise which indicate that class treatment is inappropriate, the district judge can reassess the procedures to be employed and can even reconsider the class action designation. Parkinson v. April Industries, Inc., supra, 520 F.2d at 653; General Motors Corp. v. City of New York, supra, 501 F.2d at 647; Green v. Wolf Corp., 406 F.2d 291, 298 (2d Cir. 1968), cert. denied, 395 U.S. 977, 89 S.Ct. 2131, 23 L.Ed.2d 766 (1969); Rule 23(c)(1), Fed.R.Civ.P. Judge Griesa specifically noted that his determination was a provisional one.
Accordingly, we affirm the provisional designation of the suit as a class action but reverse the order imposing on the defendant Fund the costs of extracting from computer tapes the names and addresses of the class members.
. See Developments in the Law, Multiparty Litigation in the Federal Courts, 71 Harv.L.Rev. 874, 943 (1958); Meyer, The Social Utility of Class Actions, 42 Brooklyn L.Rev. 189, 190-91 (1975).
. Each of the three consolidated suits contains two counts — one a derivative and one a class action. The order on appeal deals only with the latter, and we are not here concerned with the derivative claims. Furthermore, the Fund would not directly benefit from a recovery by the plaintiffs.
. The dissent apparently overlooks the fact that the costs were imposed on the Fund which is not a party to the class action claims. Eisen IV, supra, 417 U.S. at 178, 94 S.Ct. at 2153, makes an exception to the usual rule that the representative plaintiff must bear the cost of notice “where a fiduciary duty pre-existed between the plaintiff and defendant . (emphasis added). We may not assume that non-class member shareholders would approve of the Fund underwriting these expenses for the benefit of other shareholders.
. We find nothing in either the language or history of Rule 23 that gives a court any authority to conduct a preliminary inquiry into the merits of a suit in order to determine whether it may be maintained as a class action.
Eisen IV, supra, 417 U.S. at 177, 94 S.Ct. at 2152. We have stated the matter more broadly:
But neither in amended Rule 23 nor in any other rule do we find provision for any tentative, provisional or other makeshift determination of the issues of any case on the merits for the avowed purpose of deciding a collateral matter such as which party is to be required to pay for mailing, publishing or otherwise giving any notice required by law.
Eisen III, supra, 479 F.2d at 1015.
. See Note, Class Actions Under Federal Rule 23(b)(3) — The Notice Requirement, 29 Md.L. Rev. 139, 155 (1969). This is true of the instant case where the interests of the class members are said to range from $2.00 to $24.00.
. The court found: “If the shareholders who purchased during the relevant period were misled into purchasing at inflated prices, then, as far as the present record shows, this problem affects those shareholders who have sold out just as much as those who happened to have retained their shares.”
. Our dissenting Brother sees Rule 34 as “more specifically designed to govern computerized information.” This rule addresses itself to the production of data compilations for inspection or copying, not to the sorting or analysis of the data. Although the rule provides that the data compilation may be “translated, if necessary, by the respondent through detection devices into reasonably usable form,” the concern appears to focus on putting the data into a form intelligible to the discoverer so he can then study or employ it. As the Advisory Committee Note to the 1970 amendment states,
“[W]hen the data can as a practical matter be made usable by the discovering party only through respondent’s devices, respondent may be required to use his devices to translate the data into usable form. In many instances, this means that respondent will have to supply a print-out of computer data.”
48 F.R.D. at 527 (emphasis added). The task of culling relevant names and addresses from a long list, as confronts the parties here, is a distinctly different one from the production for inspection and copying with which Rule 34 is concerned. If “sophisticated electronic manipulation and analysis” become necessary, “the courts will have to become increasingly sensitive to problems of expense and the utilization of an opponent’s computer assets.” 8 C. Wright and A. Miller, Federal Practice & Procedure § 2218 at 659 (1970).