From BDT Prods., Inc. v. Lexmark Int’l, Inc., 2010 U.S. App. LEXIS 8203 (6th Cir. April 21, 2010):

Meisenheimer's first argument is that the district court erred to the extent that it imposed sanctions under 28 U.S.C. § 1927, as § 1927 permits the imposition of sanctions against individual lawyers, but not against law firms. According to § 1927:

Any attorney or other person admitted to conduct cases in any court of the United States or any Territory thereof who so multiplies the proceedings in any case unreasonably and vexatiously may be required by the court to satisfy personally the excess costs, expenses, and attorneys' fees reasonably incurred because of such conduct.

28 U.S.C. § 1927 (2006). Whether this language prohibits the sanctioning of law firms is an issue of law that the court reviews de novo. Claiborne v. Wisdom, 414 F.3d 715, 722 (7th Cir. 2005). While we have never directly ruled on this question, after the district court issued its order requiring Meisenheimer to pay sanctions in this case, a Sixth Circuit panel stated in dicta that "§ 1927 does not authorize the imposition of sanctions on a represented party, nor does it authorize the imposition of sanctions on a law firm." Rentz v. Dynasty Apparel Indus., Inc., 556 F.3d 389, 396 n.6 (6th Cir. 2009) (imposing sanctions against attorneys in their individual capacities solely under Fed. R. Civ. P. 11 rather than under § 1927) (citing Claiborne, 414 F.3d at 722-24).

"[O]ne panel of [the Sixth Circuit] is not bound by dicta in a previously published panel opinion." United States v. Burroughs, 5 F.3d 192, 194 (6th Cir. 1993). Nonetheless, "[a]lthough dictum is unnecessary to the decision, it may nevertheless be followed if 'sufficiently persuasive.'" PDV Midwest Ref., L.L.C. v. Armada Oil & Gas Co., 305 F.3d 498, 510 (6th Cir. 2002). The Rentz court, while offering no analysis itself, cited to Claiborne, 414 F.3d 715, in which the Seventh Circuit collected cases and issued a well-reasoned explanation of why, under § 1927, judges may not appropriately sanction law firms. ***

We find the analysis and reasoning of the Claiborne court persuasive. Even if firms can admittedly be personified in a literary sense through briefs, there is no reason to consider a law firm a "person" under the statute. More importantly, law firms are not "admitted" to "conduct cases" in court. We therefore confirm what the Rentz court stated in dicta, that 28 U.S.C. § 1927 does not authorize the imposition of sanctions on law firms.