Full Opinion

Case: 26-50156 Document: 132-1 Page: 1 Date Filed: 11/05/2026 United States Court of Appeals for the Fifth Circuit United States Court of Appeals ____________ Fifth Circuit FILED Summary Calendar November 5, 2026 No. 26-50156 Thomas B. Plunkett, III ____________ Clerk James De Los Santos, Plaintiff—Appellant, versus Mattress By Appointment, L.L.C., Defendant—Appellee. ______________________________ Appeal from the United States District Court for the Western District of Texas USDC No. 1:25-CV-1742 ______________________________ Before King, Higginson, and Douglas, Circuit Judges. Per Curiam: * James De Los Santos appeals the district court’s dismissal of his suit and the district court’s sanctions warning. We lack authority to review the sanctions warning. Finding no abuse of discretion, we AFFIRM the district court’s dismissal of Santos’s suit. _____________________ * This opinion is not designated for publication. See 5th Cir. R. 47.5. Case: 26-50156 Document: 132-1 Page: 2 Date Filed: 11/05/2026 No. 26-50156 In October 2024, Santos entered a contract with Mattress By Appoint- ment, LLC (“MBA”) to sell mattresses in Austin, Texas. The contract had a mandatory arbitration provision. On May 10, 2025, MBA terminated the contract, asserting that Santos breached the agreement by failing to place re- quired orders. On May 21, 2025, Santos filed a declaratory judgment action in Texas state court, seeking a judgment that Texas had jurisdiction over his dispute with MBA and that the arbitration provision was unenforceable. MBA re- moved the case to the Western District of Texas and filed a motion to compel arbitration. The district court granted MBA’s motion to compel arbitration, stayed the case pending arbitration, and dismissed Santos’s remaining claims. Santos appealed to our court. We denied his appeal and subsequent petition for rehearing. Santos sued MBA in Texas state court anew. MBA again removed the suit to federal district court. MBA filed a motion to dismiss and a motion for sanctions. The magistrate judge recommended dismissing Santos’s claims under the claim-splitting doctrine and issuing a “frivolous litigant warning.” Santos objected. The district court adopted the report and recommendation over Santos’s objections. The district court granted MBA’s motion to dismiss and warned Santos that he may be subject to sanctions if he continues to file frivolous claims and abuse the judicial system. Santos appealed. We review a district court’s dismissal for claim splitting for an abuse of discretion. Gen. Land Off. v. Biden, 71 F.4th 264, 269 n.6 (5th Cir. 2023). A district court abuses its discretion if it “relies on clearly erroneous factual findings, relies on erroneous conclusions of law, or misapplies the law to the facts.” In re Volkswagen of America, Inc., 545 F.3d 304, 310 (5th Cir. 2008) 2 Case: 26-50156 Document: 132-1 Page: 3 Date Filed: 11/05/2026 No. 26-50156 (citing McClure v. Ashcroft, 335 F.3d 404, 408 (5th Cir. 2003)). In the context of claim splitting when an earlier suit is pending, as here, the court properly dismisses: (1) when the parties are the same or in privity and (2) when the same claim or cause of action is involved in both. Armadillo Hotel Grp., L.L.C. v. Harris, 84 F.4th 623, 628 (5th Cir. 2023). The rule protects “the defendant from being harassed by repetitive actions based on the same claim.” See Gen. Land Off., 71 F.4th at 270 (quoting Matter of Super Van, Inc., 92 F.3d 366, 371 (5th Cir. 1996)). The district court did not abuse its discretion in granting MBA’s motion to dismiss. The district court adopted the magistrate judge’s conclusion that both factors were met here. We find no error in that conclusion. First, the parties are identical in the first suit and the instant suit. Santos admits that he is the sole plaintiff in both cases, but he notes that in his second case, he sought relief on behalf of another individual and a business. That does not change the identity of the parties. And the fact that the other individual and business are named parties in a distinct, consolidated suit has no effect on the identity of the parties in Santos’s suit. See Johnson v. Manhattan Ry. Co., 289 U.S. 479, 496–97 (1933) (“[C]onsolidation . . . does not merge the suits into a single cause, or change the rights of the parties.”). Second, Santos brings the claims based on the same nucleus of operative facts—his contract with MBA, the arbitration provision in that contract, and the circumstances under which the parties entered that contract. The factual predicate of both suits is closely “related in time, space, [and] origin[.]” Armadillo, 84 F.4th at 629 (quoting Petro-Hunt, LLC v. United States, 365 F.3d 385, 396 (5th Cir. 2004)). That he uploaded thousands of largely unrelated additional pages in the subsequent case does not change the nucleus of operative facts. 3 Case: 26-50156 Document: 132-1 Page: 4 Date Filed: 11/05/2026 No. 26-50156 Additionally, contrary to Santos’s claim, the claim-splitting doctrine does not require that the first-filed case be adjudicated. The doctrine “prohibits a party or parties in privity from simultaneously prosecuting multiple suits involving the same subject matter against the same defendants.” Id. at 628 (quoting General Land Off., 71 F.4th at 269–70). “[B]y definition, no final judgment from the prior suit exists.” Id. at 628. As to sanctions, the district court warned that Santos “may be subject to sanctions, including monetary sanctions or a pre-filing injunction barring him from filing future suits, if he continues to file frivolous claims and otherwise abuse his access to the judicial system.” This is a warning, not an order of sanctions. There is no authority under which our court could vacate—or even review—a sanctions warning. Finally, in his reply brief, Santos argues for the first time that the district court improperly dismissed the case with prejudice. Arguments raised for the first time in a reply brief are waived. Jones v. Cain, 600 F.3d 527, 541 (5th Cir. 2010). Finding no abuse of discretion, we AFFIRM. 4