dissenting. I respectfully dissent. I agree with part I of the majority opinion concerning the Lability of attorney Jane Seidl, one of the defendants, but I disagree with parts II and III concerning the LabiLty of the defendant law firm and the other individual defendants.1
As a matter of principle, the majority opinion subscribes to the position advanced by the defendants that, no matter how egregious and protracted their professional misconduct, it is more appropriate for this court to take an unnecessarily rigorous view of proof of damages than to provide relief for the plaintiff,2 a cLent whom the defendants have put out of business. I disagree with so constricted a view of professional and fiduciary responsibihty. CLents aggrieved by the misconduct of their attorneys are entitled to rely on courts to recognize that such misconduct may impair not only the clients’ business but also the clients’ ability to prove, with complete precision, the extent to which their business has been impaired. Having substantially created the problem, the defendants now should not be allowed to walk away from all responsibihty for its solution.
Secondarily, as a matter of appeLate practice, the majority opinion departs from the deference ordinarily accorded to a trial court’s discretionary role as the *81finder of facts. The trial court found the plaintiffs evidence of causation and damages to have been proved sufficiently to justify a large amount of damages. Even if the court reasonably might have found to the contrary, its view of the evidence should not be set aside lightly. This is not a case in which the plaintiff produced no evidence in support of causation and damages. The weight to be assigned to disputed evidence ordinarily is determined by the trial court and not an appellate tribunal.
I
Two predicate facts contained in the record have greater significance in this case than the majority opinion acknowledges. One relates to the trial court’s findings of liability and the other relates to the defendants’ posttrial filings.
The trial court’s findings about the defendants’ misconduct were not limited to a finding that they had committed legal malpractice. The court also found that the plaintiff had proved the defendants’ breach of contract, their negligent misrepresentations, their breach of their fiduciary duties and their breach of the contractually implied covenant of good faith and fair dealing. On appeal, the defendants have challenged the propriety of these findings only with respect to causation and to damages. Accordingly, they do not challenge the findings that their misconduct amounted not only to malpractice and to negligent misrepresentation but also to a breach of the fiduciary duty that they owed to the plaintiff.
After the trial court had rendered its judgment, the defendants filed a considerable number of posttrial motions.3 What is notable about those filings is what *82they do not include. The defendants maintain that they are entitled to a judgment on the merits without any recovery whatsoever for the plaintiff. At trial and on appeal, they contend that, although they are not blameless, they are not liable. Regardless of the breadth of their misconduct, regardless of the devastating impact of that misconduct on the plaintiff, the defendants maintain that they owe the plaintiff not one cent. On their theory, the defendants would have had as strong an objection to a judgment awarding the plaintiff $1000 as to one awarding it nearly $16 million.
Having identified the additional facts that are relevant, I next analyze the legal issues on appeal. I would resolve several of these issues differently than the majority resolves them.
II
I disagree with the majority opinion’s endorsement of the defendants’ exculpatory arguments. By not deciding the issue of causation, the majority opinion undermines the connection between causation and damages that underlay the trial court’s judgment. By discrediting the damages expert whom the trial court found credible, the majority opinion denigrates the fact-finding function of the trial court. I would affirm the judgment of the trial court on both issues.
A
I begin with the defendants’ claim that the trial court improperly determined that their malpractice caused the plaintiffs demise. Although the majority opinion sidesteps this issue, I would resolve it in accordance with the reasoning of the trial court.
We review a trial court’s determination of causation under the clearly erroneous standard. “[0]ur function [on appeal] is not to examine the record to see if the trier of fact could have reached a contrary conclusion.” *83(Internal quotation marks omitted.) Westport Taxi Service, Inc. v. Westport Transit District, 235 Conn. 1, 14, 664 A.2d 719 (1995). Rather, “it is the function of this court to determine whether the decision of the trial court is clearly erroneous. . . . This involves a two part function: where the legal conclusions of the court are challenged, we must determine whether they are legally and logically correct and whether they find support in the facts set out in the memorandum of decision; where the factual basis of the court’s decision is challenged we must determine whether the facts set out in the memorandum of decision are supported by the evidence or whether, in light of the evidence and the pleadings in the whole record, those facts are clearly erroneous.” (Citation omitted.) Pandolphe’s Auto Parts, Inc. v. Manchester, 181 Conn. 217, 221-22, 435 A.2d 24 (1980).
In its memorandum of decision, the trial court concluded that the defendants’ malpractice had constituted a proximate cause of the plaintiffs failure. Applying the “substantial factor” test of causation, the trial court concluded: “The [defendants’] inept legal representation, inordinate delays in completing their work and . . . fundamental failure to recognize [the plaintiff] as a seller of business opportunities were, as claimed by the plaintiff, substantial factors in causing damage to the plaintiff .... [T]his damage, the forced closing of the business was a natural and foreseeable consequence of the defendants’ neglect and incompetence.” In support of its determination, the trial court cited, inter alia, portions of the testimony of Harold Brown, the plaintiffs expert on franchising and business opportunities.
The defendants challenge the trial court’s conclusion on two grounds. They claim that Brown: (1) was not qualified to state an opinion regarding whether the plaintiff would have been able to make an effective *84postsale registration as a seller of business opportunities had it been notified of its violation in a timely fashion; and (2) based his opinion on faulty assumptions. I disagree with both claims.
The first issue that the defendants raise warrants little discussion because it was not properly preserved at trial. The defendants not only did not challenge Brown’s qualifications or testimony at trial; Practice Book § 60-5, formerly § 4061; Grayson v. Wofsey, Rosen, Kweskin & Kuriansky, 231 Conn. 168, 184 n.13, 646 A.2d 195 (1994); but expressly conceded his qualifications as an expert in the areas of franchising and business opportunities. The defendants likewise expressly conceded, at trial, that Brown properly could state his opinion on whether the defendants’ malpractice was “in any way a cause of the action taken by the banking commissioner.” Finally, the defendants themselves elicited Brown’s opinion that, but for various factors, the plaintiff “would have” or “probably could have” achieved a settlement with the banking commissioner. The defendants’ belated challenges to Brown’s qualifications have no merit.
The defendants’ second issue with respect to causation is their claim that the trial court improperly relied on Brown’s testimony because Brown’s testimony was premised on faulty assumptions. The defendants argue that Brown: (1) stated incorrectly that the plaintiff, as a company that had been in business less than one year, automatically would have been able to file a less burdensome “review-level” accounting statement in order to comply with the requirements of the Connecticut Business Opportunity Investment Act (act); General Statutes (Rev. to 1987) § 36-503 et seq.;4 and (2) assumed *85mistakenly that the plaintiff would have been able to survive a departmental recission order. I disagree.
In legal malpractice cases, as in other cases of negligence, we have utilized the substantial factor test as the appropriate standard for a trier of fact’s determination of proximate cause. Grayson v. Wofsey, Rosen, Kweskin & Kuriansky, supra, 231 Conn. 182. “Under the substantial factor doctrine, the trial court could accept the plaintiffs evidence of causation without requiring that the defendant’s alternative theories be expressly and entirely discredited.” Ferri v. Pyramid Construction Co., 186 Conn. 682, 687, 443 A.2d 478 (1982). “The plaintiff is not required to show only one possible theory of causation, negating all others.” Slepski v. Williams Ford, Inc., 170 Conn. 18, 22, 364 A.2d 175 (1975). Moreover, “a plaintiff may rely on circumstantial evidence and expert testimony to prove causation.” Id.
These cases support the trial court’s determination of probable cause in the circumstances of this case. The trial court stated: “It is the opinion of this court that if the defendants had recognized the need to register [the plaintiff] as a seller of business opportunities and had properly assisted the plaintiff in effecting a registration, the plaintiff would never have suffered the severe adverse consequences of failure to register which were imposed by the Department of Banking [department] and which caused the demise of its business.” The trial court further stated that the defendants’ malpractice “was the proximate cause of the failure of the [plaintiff] since it was a substantial factor in bringing about the demise of [the plaintiff].”
The defendants challenge the trial court’s determination of proximate cause by attacking what they characterize as mistaken assumptions underlying Brown’s opinion on causation. They argue first that the plaintiff did not establish, with certainty, how the department *86would have exercised its discretion under the version of the act in effect during the relevant time period. General Statutes (Rev. to 1987) § 36-508 (b).5 They also argue that, even if the plaintiff had succeeded in persuading the department to permit a postsale registration, it was unlikely that the plaintiff would have been able to comply with the sanction that the department probably would have imposed.
I am unpersuaded that the defendants’ criticisms of Brown’s testimony are accurate as a matter of fact. Even assuming their accuracy, however, we should not disturb the trial court’s finding of proximate cause. Whether the plaintiff would have succeeded in persuading the department to act favorably on its belated application cannot be dispositive in light of the trial court’s determination that the defendants’ misconduct foreclosed the option of pursuing a timely postsale registration. Moreover, the trial court was entitled to find that the plaintiff failed, not because of sanctions that the department might have imposed but because of the *87penalty actually levied as a result of the defendants’ misconduct.
The trial court was not required to rule out every other possible catase of the plaintiff’s failure in order to determine that the defendants’ misconduct was, in fact, a substantial factor in the company’s demise. See Ferri v. Pyramid Construction Co., supra, 186 Conn. 687; Slepski v. Williams Ford, Inc., supra, 170 Conn. 22. I would affirm the judgment of the trial court on this issue.
B
I turn next to the issue of damages. I disagree with the majority opinion’s reasoning in the circumstances of this case. As does the majority opinion, I reject the defendants’ claims that: (1) Thomas Ferreira, the plaintiffs expert, was not qualified to render an opinion concerning the value of the plaintiffs business; and (2) the trial court improperly awarded damages based on the plaintiffs lost profits. I would reject, as equally unpersuasive, the defendants’ remaining claims of impropriety with respect to damages.
In addressing this issue, the majority opinion starts out with an accurate description of the rocky state of the plaintiffs finances when it came to the defendants for legal representation. To my mind, it is not surprising that start-up companies, in the first years of their operation, would have a difficult time making ends meet. It is not far-fetched to assume that Steve Jobs, when he started Apple Computers, might have had difficulty in obtaining financing for so untested an idea as a personal computer. At that time, how could he have projected future profits with analytic precision? In negligence actions, defendants take their plaintiffs as they find them and cannot excuse their own misconduct because of a plaintiffs preexisting infirmities. See, e.g., Schafer v. Hoffman, 831 P.2d 897, 902 (Colo. 1992); see also 4 *88F. Harper, F. James & O. Gray, Torts (2d Ed. 1986) § 20.3, pp. 123-30. The time for the defendants to have considered the financial circumstances of the plaintiff was when they agreed to represent the plaintiff, not after they assured its demise. Accordingly, the trial court reasonably might have assigned little or no probative weight to the evidence of the plaintiffs straitened financial circumstances.
I also disagree with the majority opinion’s reasoning with respect to the remaining issues concerning damages. These issues are whether the trial court improperly: (1) awarded the plaintiff approximately $16 million in lost profits calculated over a period of twelve years; and (2) included prejudgment interest in the damages award. I would reject both of the defendants’ claims.
The trial court based its award of damages largely on the testimony presented by Ferreira, the plaintiffs expert witness. The majority opinion accepts the defendants’ arguments that, even if Ferreira was a qualified expert and properly used a lost profits measure of damages, he provided an insufficient basis for his award of lost profits over a period of twelve years and relied on mistaken assumptions about the plaintiffs future business prospects. On this theory, the majority opinion concludes that the trial court’s award was an abuse of its discretion. In light of the high degree of deference that an appellate court must afford to a trial court’s findings on damages; Westport Taxi Service, Inc. v. Westport Transit District, supra, 235 Conn. 27-28; I would reach a contrary conclusion.
1
I turn first to whether twelve years was a reasonable time frame for projecting future lost profits. I am persuaded that the trial court did not abuse its discretion in accepting a valuation of the business that projected lost profits over a twelve year period.
*89“The amount of a damage award is a matter peculiarly within the province of the trier of fact .... The size of the verdict alone does not determine whether it is excessive. The only practical test to apply to this verdict is whether the size of the verdict so shocks the sense of justice as to compel the conclusion that the [trier of fact] was influenced by partiality, prejudice, mistake or corruption.” (Internal quotation marks omitted.) Grayson v. Wofsey, Rosen, Kweskin & Kuriansky, supra, 231 Conn. 183-84.
The defendants urge us to adopt a rule that damages based on a twelve year projection of future lost profits inherently are so speculative as to be contrary to law. They point to cases from other jurisdictions in which courts have declined, in the circumstances therein, to award projected lost profits for periods of time deemed too speculative. See, e.g., Olympia Equipment Leasing Co. v. Western Union Telegraph Co., 797 F.2d 370, 383 (7th Cir. 1986) (“[t]here are no grounds for thinking [the plaintiff] could have survived in this highly competitive market for 10 years while earning a 191 percent, or even a 42 percent, rate of return on its investment”).
The majority opinion rejects the defendants’ bright line approach, but decides that damages over a twelve year period are inappropriate without “objective verifiable facts” to prove that the plaintiff would have survived and would have remained profitable for that period. In the circumstances of a plaintiff in the early days of an uncertain new venture, this harsh requirement inevitably will preclude any award of damages. If it is the misconduct of the defendants that is a substantial cause of a plaintiffs early demise, and the reason for its inability to make a more precise showing of damages, I disagree with requiring the level of proof of damages demanded by the majority.
Lost profits must be proved by a reasonable certainty and limited to a reasonable time period. “Reasonable *90certainty of proof is all that is required, and mere uncertainty as to the amount of lost profits may be dispelled by the same degree of proof as is required in other civil actions, that is, the amount may be determined approximately upon reasonable inferences and estimates.” (Internal quotation marks omitted.) Torosyan v. Boehringer Ingelheim Pharmaceuticals, Inc., 234 Conn. 1, 33, 662 A.2d 89 (1995). Similarly, “[t]he development of the law has been to find damages for lost profits of an unestablished business recoverable when they can be adequately proved with reasonable certainty.” (Emphasis added.) 1 R. Dunn, Recovery of Damages for Lost Profits (4th Ed. 1992) § 4.2, p. 280.
“It has been suggested that profits cannot reliably be forecast for any business beyond a ten year period, and that consequently this is the maximum for which they should be awarded. But the span of time for which profits can be predicted varies from business to business according to a great many factors; this makes any standard less flexible than a ‘reasonable’ time seem unwise.” Note, “Private Treble Damage Antitrust Suits: Measure of Damages for Destruction of All or Part of a Business,” 80 Harv. L. Rev. 1566, 1577 (1967). Such a flexible approach might take into account factors including: (1) a business’ past profit record, if any; (2) “the experience and ability of its management”; (3) “the quality and goodwill of its product”; (4) “the firm’s comparative standing among its competitors”; (5) “the future of the particular industry as a whole”; (6) the behavior of comparable or competitor “yardstick” firms; and (7) “the average lifespan of the type of business destroyed . . . .” Id.
I note, moreover, that other jurisdictions have awarded future lost profits projected over a period of ten or more years, even to unestablished businesses. In Super Valu Stores, Inc. v. Peterson, 506 So. 2d 317, 330 (Ala. 1987), the Alabama Supreme Court affirmed *91an award of damages to a new business based on future lost profits projected over a fifteen year time period. See Chung v. Kaonohi Center Co., 62 Haw. 594, 610-11, 618 P.2d 283 (1980) (affirming award of lost profits projected over ten year period for restaurant that never commenced operation); Fera v. Village Plaza, Inc., 396 Mich. 639, 641-45, 242 N.W.2d 372 (1976) (affirming lost profit damages awarded to unestablished business on basis of defendant’s breach of ten year lease).
A flexible approach is best suited to ensuring that new businesses are compensated fully if they suffer damages as the result of professional malpractice, breach of contract and failure to comply with fiduciary duty. “In recognition of the fact that the plaintiffs difficulty in quantifying his [or her] damages often flows directly from the defendant’s breach,” our cases state that we require “that degree of proof of damages which the facts peimit, but no more.” Bead Chain Mfg. Co. v. Saxton Products, Inc., 183 Conn. 266, 278-79, 439 A.2d 314 (1981). As the Oregon Supreme Court has stated, “the data and evidence presented by plaintiff was all that could be expected in the circumstances of this case. To hold otherwise would be tantamount to holding that the defendant could breach this particular contract with impunity.” Welch v. U. S. Bancorp Realty & Mortgage Trust, 286 Or. 673, 705, 596 P.2d 947 (1979).
2
The majority opinion’s principal reason for overturning the trial court’s award of damages is that, in its view, certain of Ferreira’s underlying assumptions were so speculative as to make the trial court’s acceptance of his projection an abuse of its discretion. The majority opinion agrees with the defendants’ argument that Ferreira’s expert opinion was flawed because he assumed that: (1) the plaintiff would have sold franchises; (2) the *92thirty-five people who had purchased fitness equipment from the plaintiff would have converted their operations into franchises; and (3) the plaintiff would have sold at least twenty new franchises each year for twelve years, and would have derived additional revenues from the sale of “super centers.” I am not persuaded that the trial court abused its discretion in accepting Ferreira’s opinion.
In this situation, as in the antitrust context, “[t]he vagaries of the marketplace usually deny us sure knowledge of what [the] plaintiffs situation would have been in the absence of the defendant’s . . . violation.” (Internal quotation marks omitted.) Westport Taxi Service, Inc. v. Westport Taxi District, supra, 235 Conn. 28. Accordingly, “[a] damage theory may be based on assumptions so long as the assumptions are reasonable in light of the record evidence.” (Internal quotation marks omitted.) Id. “The reasonableness of the assumptions underlying the plaintiffs damage theory is determined by the trier of fact.” Id. In fact, some courts “have refused to find damage evidence insufficient unless there was no basis for critical assumptions made by the trial court.” Id.
In this case, Ferreira testified that the plaintiff already had sold about sixty-five locations, nationwide, through licensing arrangements, in a period of about one and one-half years. Ferreira projected a slower growth rate of twenty locations per year for the plaintiffs franchise sales. He explained that purchasing a franchise required “more of a commitment” for buyers than purchasing a business opportunity, including paying the franchise, royalties and advertising fees. Accordingly, in order to ensure a conservative projection, he estimated sales of twenty franchises per year, the actual growth rate of World Gym Licensing Limited. He checked this assumption with at least two people who had been associated *93with the sales of the plaintiffs business locations, and he concluded that it was reasonable, if not conservative.
As for the role of the “super centers” in Ferreira’s projection, Ferreira estimated the plaintiffs revenues based, in part, on the probable equipment sales to future clubs under the plaintiffs name. The plaintiffs clubs initially were about 2000 square feet and were designed to serve women exclusively. The plaintiff planned, however, to expand its clubs to a larger floor plan of 4000 or 5000 square feet, the super center format, serving both men and women.
In projecting equipment sales to the plaintiffs clubs, Ferreira based his estimates on figures contained in the plaintiffs Uniform Franchise Offering Circular (circular). Ferreira projected equipment sales on the basis of the expected average sales to clubs with the super center floor plan, as outlined in the circular. According to Ferreira’s interviews and research, the super center was the style of club that the plaintiff had planned for the future, and, in fact, the format that had become more popular in the industry. Again, to be conservative, Ferreira estimated $90,000 in initial equipment sales, the lower end of the range of average expected equipment sales to super centers listed in the plaintiffs circular.
On the basis of this record, I would conclude that the trial court, in the exercise of its discretion, reasonably might have found that the plaintiff had adduced sufficient evidence to support Ferreira’s assumptions. The fact that the record is thin would have supported the trial court’s decision to the contrary, but it does not make it clearly erroneous for the court to find as it did. See Westport Taxi Service, Inc. v. Westport Taxi District, supra, 235 Conn. 28; see also Practice Book § 60-5, formerly § 4061.
3
The defendants also argue that the trial court improperly included prejudgment interest in the damages *94award. This is an issue that the majority opinion does not reach. I would conclude that the trial court’s ruling was proper.
The defendants argue that the trial court improperly awarded 8 percent prejudgment interest on the damages award. We have examined the portions of Ferreira’s testimony cited in the defendants’ brief, however, and conclude that his mention of the 8 percent interest rate referred to the adjustment he made for the time-value of money in calculating the value of the business itself. As discussed both in the majority opinion and in this dissent, one method of determining the worth of a business is to calculate the present value of its future income stream. Accordingly, Ferreira’s interest calculation was, in fact, consistent with his method of calculating the value of the business on its date of destruction.
Accordingly, I would not reverse the trial court’s award of damages to the plaintiff. Although the trial court was required to make a close call in a number of instances, that is the role that is assigned to trial courts. In making close calls, the trial court was entitled to give some consideration to the role that the defendants’ misconduct played in the difficulties that the plaintiff encountered in proving its damages. The majority opinion finds no impropriety in the legal standards upon which the trial court relied. Cf. Unkelbach v. McNary, 244 Conn. 350, 367, 710 A.2d 717 (1998). Rather, in concluding that the trial court’s close calls were improper, the majority opinion relies solely on its view that the defendants adduced insufficient evidence of damages. In these circumstances I see no reason to depart from our usual practice of affirming a trial court’s findings of fact unless they are clearly erroneous. See Gateway Co. v. DiNoia, 232 Conn. 223, 229, 654 A.2d 342 (1995) (“ ‘[t]o the extent that the trial court has made findings of fact, our review is limited to deciding whether such findings were clearly erroneous’ ”); see *95also Practice Book § 60-5, formerly § 4061 (“[t]he court may reverse or modify the decision of the trial court if it determines that the factual findings are clearly erroneous in view of the evidence and pleadings in the whole record”).
In conclusion, the majority opinion, in my view, reaches out to reverse a trial court judgment on grounds that ar e far from compelling. We condone professional misconduct if we discharge these defendants of all liability to a plaintiff that has tried, as best it could, to quantify the loss that the defendants’ misconduct has caused it to suffer. Such a result, it seems to me, turns the law of professional responsibility on its head. Those members of the legal profession who engage in egregious and protracted misconduct bear the responsibility, fiscally as well as morally, for the harm that they have caused. It is our responsibility to search for ways to reenforce that professional commitment.
Accordingly, I respectfully dissent.
In addition to Jane Seidl, the defendants were Schatz & Schatz, Ribicoff & Kotkin, Stanford Goldman and Ira Dansky.
Beverly Hills Concepts, Inc., is the plaintiff to which this opinion refers. The trial court’s determination that the individual plaintiffs named in the complaint lacked standing to maintain the action has not been challenged on appeal.
On February 6, 1997, the defendants filed a motion to reargue or open or set aside the judgment, for a new trial, or for judgment, which the trial court denied. The defendants also filed, on June 17, 1997, a motion for articulation, which the trial court, likewise, denied.
General Statutes (Rev. to 1987) § 36-508 provides in relevant part: “(a) Unless exempted by subsection (e) of this section, any person who advertises, sells, contracts, offers for sale or promotes any business opportunity in this state or from this state must register with the commissioner and file, in a form prescribed by said commissioner, an application . . .
General Statutes (Rev. to 1987) § 36-508 (b) provides in relevant part: “The seller shall file with the commissioner (1) a balance sheet, income statement and statement of changes in financial condition of such seller as of a date not more than four months prior to the filing of the registration statement (2) a balance sheet of such seller, an income statement and statement of changes in financial position for the most recent fiscal year audited by an independent public accountant or an independent certified public accountant and (3) a balance sheet and income statement and statement of changes in financial position for the prior two fiscal years reviewed by an independent certified public accountant who provides an opinion stating that he is not aware of any material modifications that should be made to the financial statements in order for them to be in conformity with generally accepted accounting principles. . . . The commissioner may waive the requirement for audited statements for sellers who have been in business for less than one year and who have not previously had such certified audits, provided the unaudited financial statements are reviewed by an independent certified public accountant who provides an opinion stating that he is not aware of any material modifications that should be made to the financial statements in order for them to be in conformity with generally accepted accounting principles. . . .”