III
Because the facts which caused the district court to impose sanctions are not in dispute, we review the district court’s conclusion that plaintiffs’ counsel violated Fed. R.Civ.P. 11 de novo, Zaldivar v. City of Los Angeles, 780 F.2d 823, 828 (9th Cir. 1986), and reverse.
Rule 11 provides in pertinent part:
The signature of an attorney [on a pleading, motion, or other paper] ... constitutes a certificate by him that he has read the pleading, motion, or other paper; that to the best of his knowledge, information, and belief formed after reasonable inquiry it is well grounded in fact and is warranted by existing law or a good faith argument for the extension, modification, or reversal of existing law, and that it is not interposed for any improper purpose, such as to harass or to cause unnecessary delay or needless increase in the cost of litigation.
Subjective bad faith is not an element of a Rule 11 violation, it is enough if the paper at issue lacks a basis in fact or a good faith argument in law, or needlessly increases litigation. Zaldivar, 780 F.2d at 830-32.
Plaintiffs’ counsel did not violate Rule 11 in filing the February 11, 1985 Supplemental Authority in Opposition to Defendant’s Motion for Reconsideration. First, the November 10 filed and rejected complaint, attached as an exhibit to previous papers in opposition to defendants’ motion to reconsider, provides the factual basis for counsel’s argument. In the Supplemental Authority, plaintiffs’ counsel specifically referred to the previous declaration of counsel, the rejected complaint, and their location in the record.
Second, plaintiffs’ reliance on Loya, 721 F.2d at 281, for the proposition that the rejected November 10 complaint constituted a filing for statute of limitations purposes was then a good faith legal argument. At the time plaintiffs’ Supplemental Authority was filed, we had not yet held that a section 301 complaint must be filed and served within the six-month limitations period. See Gallon, 779 F.2d at 1440-41.
Third, although the district court was initially confused by the November 10 date in the Supplemental Authority, the matter was cleared up at oral argument. Thus, this is not a case in which a misstatement of fact has increased the costs of litigation to the opposing party. See, e.g., In re National Student Marketing Litigation, 78 F.R.D. 726, 731 & n. 13 (D.D.C.1978), aff'd sub nom. Lipsig v. National Student Marketing Corp., 663 F.2d 178 (D.C.Cir. 1980). Moreover, there is no indication that the Supplemental Authority was filed for an improper purpose.
IV
We therefore affirm the district court’s grant of summary judgment in favor of GK Trucking but reverse the district court’s imposition of sanctions against plaintiffs’ counsel. All parties are to bear their own costs of appeal.
AFFIRMED IN PART, REVERSED IN PART.