Judson Atkinson’s claim that LMC’s officers breached their fiduciary duties. Judson Atkinson contends that Carroll, Elsen and Hohberger, as officers of LMC, owed fiduciary duties to Judson Atkinson because Judson Atkinson is a creditor of LMC and that they breached those duties. The defendants assert that Judson Atkinson lacks standing to bring such a claim. In general, the officers and directors of a corporation do not owe fiduciary duties to creditors of the corporation. See Macaluso, 50 Ill.Dec. 934, 420 N.E.2d at 257. But in special circumstances, such as insolvency, directors do owe a duty to creditors. See Technic Eng’g, Ltd. v. Basic Envirotech, Inc., 53 F.Supp.2d 1007, 1011 (N.D.Ill.1999). Some courts have found that the special circumstance fiduciary duty “runs to all creditors as a group, and not to any individual creditor,” and therefore that “only the corporation or its representative in bankruptcy can maintain a
claim for an alleged breach of this duty.” Prime Leasing, Inc. v. Kendig, 332 Ill.App.3d 300, 265 Ill.Dec. 722, 773 N.E.2d 84, 97 (Ill.App.Ct.2002) (applying Delaware law); see also North Am. Catholic Educ. Programming Found., Inc. v. Gheewalla, 930 A.2d 92, 103 (Del.2007) (“The creditors of a Delaware corporation that is either insolvent or in the zone of insolvency have no right, as a matter of law, to assert direct claims for breach of fiduciary duty against its directors.”). Although the Illinois Supreme Court has not addressed whether a corporation’s creditor may bring a direct claim for breach of special circumstance fiduciary duty, several courts have found that under Illinois law, creditors can sue for such a breach. See Technic Eng’g, Ltd., 53 F.Supp.2d at 1010-12; O’Connell v. Pharmaco, Inc., 143 Ill.App.3d 1061, 98 Ill.Dec. 154, 493 N.E.2d 1175, 1182 (Ill.App.Ct.1986); Circle Sec. Agency, Inc. v. Ross, 99 Ill.App.3d 1111, 55 Ill.Dec. 110, 425 N.E.2d 1283, 1286 (Ill.App.Ct.1981). Even if we were to assume that Judson Atkinson has standing to sue for a breach of special circumstance fiduciary duty, however, Judson Atkinson’s breach of fiduciary duty argument is mainly a rehashing of its veil-piercing argument. Judson Atkinson does not cite the elements of a breach of fiduciary duty claim or show how any evidence in the record tends to support such a claim. As a result, it has waived this argument. See United States v. Dunkel, 927 F.2d 955, 956 (7th Cir.1991) (“A skeletal ‘argument’, really nothing more than an assertion, does not preserve a claim.”) (citation omitted).
D. The district court’s grant of summary judgment sua sponte in favor of Dhimantec and LMC
Judson Atkinson contends that the district court erred in granting summary judgment in favor of LMC and Dhi-mantee, with respect to its alter ego and fraudulent conveyance claims, because neither of them filed a motion for summary judgment. District courts have the authority to enter summary judgment sua sponte “so long as the losing party was on notice that she had to come forward with all of her evidence.” Celotex Corp. v. Catrett, 477 U.S. 317, 326, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986). In addition, we have held that if a district court grants one defendant’s motion for summary judgment, it may sua sponte enter summary judgment in favor of non-moving defendants if granting the motion would bar the claim against those non-moving defendants. Malak v. Associated Physicians, Inc., 784 F.2d 277, 280 (7th Cir.1986); see also Acequia, Inc. v. Prudential Ins. Co. of Am., 226 F.3d 798, 807 (7th Cir.2000) (sua sponte grant of summary judgment appropriate “where one defendant succeeds in winning summary judgment on a ground common to several defendants, if the plain