CYR, Circuit Judge.

Appellant Stephen Linder, Esquire, challenges the sanction imposed against him pursuant to Fed.R.Civ.P. 11 for filing a groundless complaint against defendants-appellees. After careful review, we affirm the district court sanction order in all respects.

I BACKGROUND

In the fall of 1985, the City of East Providence, Rhode Island, announced that an independent testing service would administer a competitive examination for the position of Chief of Police. A city ordinance empowered the City Manager, defendant-appellee Peter Witschen, to fill the position from among the top three performers on the examination. See Civil Service Ordinance of East Providence, R.I. §§ 11-66(c), (d). It was no secret that some members of the City Council, including defendants-appellees in this action, favored the appointment of defendant Anthony DeCastro. DeCastro achieved the highest examination score and, in January 1986, was appointed by the City Manager.

Following the appointment, a rift arose between Chief DeCastro and the Fraternal Order of Police Union (Union). At a public session of the City Council years later, it was disclosed that several defendants had discussed beforehand with DeCastro the likelihood that a competitive examination would be administered and that DeCastro's test-taking skills were weak. Finally, it was also disclosed at the City Council meeting that DeCastro had attended a preparatory course in "executive development" on his own time, for which he was reimbursed pursuant to a City policy permitting reimbursement for "in-service training."

Present at the City Council meeting were several of the plaintiffs, all disappointed applicants for the position, and appellant Linder, counsel to the Union. Shortly after the City Council meeting, two of the plaintiffs met briefly with Linder and discussed factual grounds for a possible lawsuit in their behalf. Thereafter, Linder conducted limited discussions with other plaintiffs along similar lines.

On January 3, 1990, Linder initiated the present action under 42 U.S.C. § 1983 in the United States District Court for the District of Rhode Island, charging deprivations of plaintiffs' due process right to a fair and impartial promotional examination as provided by the City ordinance, and of an alleged right of "equal protection" to compete for the position. Although the complaint pleaded relevant circumstances which the district court later characterized as "suspicious," see supra pp. 726-727, it neither alleged — nor asserted facts sufficient to support an inference — that the examination was either "rigged" to favor DeCastro or administered or graded unfairly.

Prior to filing the complaint, Linder made a copy available to the City Solicitor, who advised Linder that it was "unjustified," and warned that the City was likely to demand attorney fees for defending against it. Linder was not deterred.

Ultimately, the district court entered summary judgment for all defendants on the ground that "the complaint made no allegations of 'exam rigging,'" which was the essence of plaintiffs' claim. Silva v. Witschen, 745 F. Supp. 798, 803 (D.R.I. 1990). The defendants thereafter requested attorney fees, either under 42 U.S.C. § 1988 or as a sanction under Fed.R.Civ.P. 11.

In due course, the district court conducted a lengthy hearing to determine whether the fee request should be allowed on either ground. The amount of any fee award was not before the court at the hearing. Following the hearing, the court denied the request for an award under section 1988, on the ground that the plaintiffs had not acted in bad faith. The court found, however, that Linder was subject to sanction under Rule 11 for filing a groundless complaint. The defendants later requested fees and costs totalling almost $250,000, which the court reduced to $75,349.96, approximately two-thirds of which was attributed to the merits phase and one-third to the sanctions phase of the district court litigation.

II DISCUSSION

All aspects of the Rule 11 sanctions decision are reviewed for abuse of discretion. Cooter Gell v. Hartmarx Corp., 496 U.S. 384, 405, 110 S.Ct. 2447, 2460, 110 L.Ed.2d 359 (1990); Metrocorps, Inc. v. Eastern Mass. Junior Drum Bugle Corps Ass'n, 912 F.2d 1, 2 (1st Cir. 1990). As the party challenging the sanctions award, Linder bears the formidable burden of establishing abuse of discretion. See Navarro-Ayala v. Nunez, 968 F.2d 1421, 1425 (1st Cir. 1992). An abuse of discretion occurs only if "'a material factor deserving significant weight is ignored, . . . an improper factor is relied upon, or . . . all proper and no improper factors are assessed, but the court makes a serious mistake in weighing them.'" Anderson v. Beatrice Foods Co., 900 F.2d 388, 394 (1st Cir.) (quoting Fashion House, Inc. v. K Mart Corp., 892 F.2d 1076, 1081 (1st Cir. 1989)), cert. denied, 498 U.S. 891, 111 S.Ct. 233, 112 L.Ed.2d 193 (1990).

A. Amended Rule 11

On December 1, 1993, during the pendency of the present appeal, an amended version of Rule 11 became effective, governing "all proceedings in civil cases thereafter commenced and, insofar as just and practicable, all proceedings in civil cases then pending." Order Amending Federal Rules of Civil Procedure, 113 S.Ct. CDLXXVIII (Apr. 22, 1993) (emphasis added). Linder therefore contends that amended Rule 11 applies on appeal in the present case.

We need not decide whether a case pending on appeal December 1, 1993 is subject to the amended rule. The promulgation order precludes application of the amended rule even in "cases then pending" insofar as it would be unjust or impracticable to do so. Id. To remand for a district court determination under amended Rule 11 in these circumstances is not only infeasible but would work an injustice to plaintiffs-appellees. See Hashemi v. Campaigner Publications, Inc., 784 F.2d 1581, 1584 (11th Cir. 1986) (finding no reason to test Rule 11 sanctions under amendment to 1983 rule not in effect when sanctioned conduct occurred) (decided under virtually identical terms of 1983 promulgation order: "shall govern . . ., insofar as just and practicable, in proceedings then pending." Order Amending Rules of Civil Procedure, 461 U.S. 1097 (1983)). Cf. Freund v. Fleet-wood Enters., Inc., 956 F.2d 354, 363 (1st Cir. 1992) (declining to apply amended Fed.R.Civ.P. 15(c) which would work "manifest injustice"); 89 Agretti v. ANR Freight Sys., Inc., No. 89 C 5492, 1994 WL 46670, at *1 (N.D.Ill. Feb. 14, 1994) (finding retrospective application of 1993 amended Rule 11 "neither just nor practicable"); In re Taxable Mun. Bond Sec. Litig., No. MDL 863, 1994 WL 34924, at *4 (E.D.La. Feb. 3, 1994) (declining to apply 1993 amended rule where sanctioned conduct occurred prior to Dec. 1, 1993 and pre-amendment standards had been applied at sanctions hearing). This is particularly true since Linder's sanctionable conduct was solely responsible for the satellite proceedings relating to Rule 11 sanctions. Moreover, it would be impracticable, not only to undo the harm actually occasioned defendants, but to review the district court order under the altered standards established by amended Rule 11. See Hashemi, 784 F.2d at 1583-84 (rejecting claim, under virtually identical 1983 promulgation order, that amended Rule 11 standards should apply "because the case was pending on appeal by the plaintiff at the time the Rule became effective"); cf. Freund, 956 F.2d at 363 (refusing to apply amended rule which would work "manifest injustice"). Since an unwarranted remand would otherwise be necessary in these already protracted satellite proceedings, at inordinate delay and expense to innocent parties, we review the district court sanction order under the pre-amendment Rule 11 standards in force at the time the sanctioned conduct occurred.

B. Appropriateness of Rule 11 Sanctions

Prior to December 1, 1993, Rule 11 mandated sanctions for interposing a filing either for an improper purpose or under circumstances in which a competent attorney, on objectively reasonable inquiry, could not have believed that the filing was grounded in fact and warranted either by existing law or by a good-faith argument for the extension, modification or reversal of existing law. Lancellotti v. Fay, 909 F.2d 15, 19 (1st Cir. 1990).

1. Legal Basis for Action

Linder "concedes" that the complaint violated Rule 11, in that he failed to make the objectively reasonable legal inquiry required under our case law. He argues, however, that Leatherman v. Tarrant County Narcotics Intelligence and Coordination Unit, ___ U.S. ___, 113 S.Ct. 1160, 122 L.Ed.2d 517 (1993), struck down the heightened pleading requirement previously espoused by this court in section 1983 actions. Since Leatherman should be given retroactive effect, see Harper v. Virginia Dep't of Taxation, ___ U.S. ___, ___-___, 113 S.Ct. 2510, 2516-17, 125 L.Ed.2d 74 (1993) (general rule of retroactivity in civil cases), Linder contends that sanctions were improperly imposed. This argument is a red herring.

The district court order neither mentioned nor applied a heightened pleading standard, nor did it cite to any case involving a heightened pleading requirement. See Silva, 745 F. Supp. at 801. Rather, the court determined that there was no legal basis whatever for Linder's reliance on a federally protected property interest, in principal part because plaintiffs made no allegation of "exam-rigging." See Burns v. Sullivan, 619 F.2d 99, 104 (1st Cir.), cert. denied, 449 U.S. 893, 101 S.Ct. 256, 66 L.Ed.2d 121 (1980). Compare Silva, 745 F. Supp. at 803, with Hermes v. Hein, 511 F. Supp. 123, 125 (N.D.Ill. 1980) (complaint alleging exam-rigging states § 1983 claim in circumstances where unwavering custom and policy is to promote applicant achieving highest score). The court concluded that the only protected property interest at issue was plaintiffs' due process right to compete fairly for the position of Chief of Police, and since they had alleged no facts evidencing such a deprivation the action was groundless as a matter of law. Silva, 745 F. Supp. at 805. Neither before the district court, nor on appeal, has Linder raised doubt as to the soundness of the district court ruling that the complaint failed to state a cause of action.

2. Improper Purpose

The district court further found that Linder attempted — by bringing the present action — to intimidate "the City into terminating DeCastro . . . . [thus] using this case to further an improper objective." Silva v. Witschen, C.A. No. 90-0005L, slip op. at 18-19 (D.R.I. Nov. 5, 1992) (order imposing sanctions). Although Linder admits to a "dual motive," he argues that Rule 11 sanctions may not be imposed for commencing an action for an "improper purpose" if there was also a proper motive, in this case vindicating plaintiffs' rights. The district court found that —

Linder, who was also the attorney for the Union, was wearing two hats here. Although he purported to represent the plaintiffs in this case, all his actions were calculated to achieve the goal of the Union, the ouster of DeCastro. While plaintiffs honestly believed in their cause of action, Linder was using their lawsuit as a bargaining chip to pressure the City on behalf of the Union to terminate DeCastro as Chief of Police.

Id. at 19 (emphasis added).

Linder's contention that his conduct is not sanctionable because he intended to protect plaintiffs' legal rights is yet another red herring. We are aware of no authority or other basis for the view that an attorney who files a groundless complaint, for an improper purpose and without reasonable inquiry, see Fed.R.Civ.P. 11, is exonerated from sanctions because he was simply asserting groundless nonexistent legal claims in behalf of his clients. Cf. Lieb v. Topstone Indus., Inc., 788 F.2d 151, 157 (3d Cir. 1986) ("[P]leader may not escape liability because he did not intend to bring about additional delay or expense. If reasonable preparatory steps would have avoided those consequences, sanctions are appropriate."). Accordingly, we uphold the district court finding of improper motive. Cf. Mir v. Little Co. of Mary Hosp., 844 F.2d 646, 653 (9th Cir. 1988) (using litigation to force party to grant privileges previously denied is "improper purpose").

C. Appropriateness, Nature and Severity of Sanctions 1. Rule 11 Hearing

The procedure for determining whether a sanction should be imposed and, if so, its nature and severity, is left in the first instance to the trial court's sound discretion. Linder contends that the district court abused its discretion, see Cooter Gell, 496 U.S. at 405, 110 S.Ct. at 2460, by unnecessarily convening a hearing on the request for Rule 11 sanctions. See also Fed.R.Civ.P. 11 advisory committee's note (sanctions procedure depends on circumstances and severity of sanction under consideration); Muthig v. Brant Point Nantucket, Inc., 838 F.2d 600, 607 (1st Cir. 1988) (similar). He argues that there was no reason to conduct a Rule 11 hearing once the court found no legal basis for the complaint, see Silva, 745 F. Supp. at 803, since sanctions were mandatory under the pre-amendment version of Rule 11, Jensen v. Frank, 912 F.2d 517, 524 n. 6 (1st Cir. 1990).

Linder once again mischaracterizes the proceedings below. The grant of summary judgment against plaintiffs did not preordain the imposition of any Rule 11 sanction against Linder. Rather, the hearing was necessary to determine whether Linder had violated Rule 11 and, if so, to determine an appropriate sanction. Additionally, defendants requested a fee award against plaintiffs under 42 U.S.C. § 1988 as well, which the court considered at the same hearing and later denied. The claim that the district court abused its discretion by conducting a hearing to resolve defendants' fee requests under Rule 11 and section 1988 is frivolous.

Linder has fallen far short of a showing of abuse of discretion. Rule 11 contemplates "giv[ing] effect to [its] central goal of deterrence," Cooter Gell, 496 U.S. at 405, 110 S.Ct. at 2460, while avoiding unnecessary satellite litigation; the proper balance is left to the reasoned discretion of the district court, id. Cf. Fashion House, 892 F.2d at 1082 (district court is in best position to determine appropriate remedy). The hearing was necessary for two reasons: to determine whether there was a proper basis for assessing attorney fees against plaintiffs under 42 U.S.C. § 1988, and whether Linder's filing of the groundless complaint warranted imposition of a Rule 11 sanction. Silva, slip op. at 2-3 (Nov. 5, 1992); Silva, 745 F. Supp. at 806. Thus, among the matters at issue in the Rule 11 sanctions hearing were whether Linder: (1) brought the action for an improper purpose and (2) after reasonable inquiry, could have formed a reasonable belief that the complaint was well grounded in fact and "warranted by existing law or a good faith argument for the extension, modification, or reversal of existing law." Fed.R.Civ.P. 11 (1987); see Lancellotti, 909 F.2d at 19. The court found that "Linder failed to make a reasonable inquiry to determine that the complaint was well founded in fact . . . [and] even more important [the] lawsuit was baseless as a matter of law." Silva, slip op. at 17 (Nov. 5, 1992). See Unanue-Casal v. Unanue-Casal, 898 F.2d 839, 841-42 (1st Cir. 1990) (Rule 11 sanctions against counsel warranted for filing frivolous removal petition with "no plausible legal basis" and for "improper purpose").

2. Reasonableness of Sanctions

Linder's remaining claim is that the attorney fee award is excessive. Compensatory sanctions under Rule 11 must be reasonable in amount. Navarro-Ayala, 968 F.2d at 1427 (citing cases).

a. Merits Phase

The district court awarded the City $53,528.81 in attorney fees and costs incurred during the merits phase of the litigation by all defendants, representing approximately 487 hours devoted to legal services by counsel appearing for the five individual defendants, and by the City Solicitor in behalf of the City and the same five individual defendants in their official capacities. Linder does not challenge the individual fee applications, but asserts that the aggregate hours were not reasonably required because defendants did not take proper measures to mitigate fees by delegating jointly-required in-court services and submitting unitary filings to avoid unnecessary duplication of services. See Navarro-Ayala, 968 F.2d at 1427 (compensatory sanctions allowed only for costs reasonably incurred) citing Thomas v. Capital Sec. Services, Inc., 836 F.2d 866, 879 (5th Cir. 1988); see also Dubisky v. Owens, 849 F.2d 1034, 1037 (7th Cir. 1988) (similar).

The district court rejected Linder's argument, finding instead that "if plaintiffs' case had not been so utterly without merit, this 'redundant' representation might have proved essential to these defendants," Silva, slip op. at 13 (May 6, 1993), and therefore that the employment of multiple attorneys during the merits phrase was reasonably required. We agree that it was reasonable for the five defendants, in their individual capacities, to obtain representation by their own counsel while the merits of plaintiffs' claims remained in litigation, since counsel to the City represented the individual defendants in their official capacities only. Linder points to no authority for the implicit assumption that reasonable mitigation efforts require that the private interests of parties sued in their individual capacities must go unrepresented. Cf Mariani, 983 F.2d at 8 n. 5. Nor has he shown that the respective private interests of these individual defendants during the merits phase did not conflict to the point that mutual representation was precluded. Cf. Brandt v. Schal Assoc., Inc., 960 F.2d 640, 648 (7th Cir. 1992) ("[w]e have little sympathy for the litigant who fires a big gun, and when the adversary returns fire, complains because he was only firing blanks").

The court further found that "the total time spent by each attorney on the merits was not excessive." Silva, slip op. at 13 (Nov. 5, 1992). The court also disallowed all fees for legal services, except those services directly rendered to the City, after the point in time when it became clear that no conflicts of interest precluded the individual defendants' joint representation by counsel to the City. See Brandt, 960 F.2d at 649 (no failure to mitigate where sanctioned attorney's broad complaint necessitated investment of extensive attorney time in defense and district court carefully monitored procedure). A party is required to mitigate expenses only insofar as is reasonable. Our review of the record discloses no basis for supposing that the district court abused its discretion by allowing a $53,528.81 reimbursement to the City for legal services rendered during the merits phase. See Navarro-Ayala, 968 F.2d at 1426 ("When the district court settles upon a monetary sanction and fixes a dollar amount, a reviewing tribunal should defer, within broad limits, to the district court's exercise of its informed discretion. Nevertheless, the court of appeals must be careful not merely to 'rubber-stamp the decisions of the district court.'") (citation omitted).

b. Sanctions Phase

The district court disallowed all fees requested in relation to the sanctions phase of the litigation except for those incurred by the City. The court found that counsel to the individual defendants had been notified in advance that the City no longer believed there existed any conflict of interest precluding joint representation. Thus, the court allowed only $21,821.15 in total fees and costs for 188 out of over 1500 hours expended by all counsel representing defendants during the sanctions phase. Linder does not challenge the reasonableness of the fees incurred by the City in the sanctions phase.

We therefore affirm the district court judgment.

Affirmed.