Court Documents: Oona Sperr's $400M lawsuit against Sid Bass and Althea Viafora Bass

This page hosts court documents from Sperr v. Bass, the lawsuit Oona Sperr filed August 31 in the U.S. District Court for the Southern District of New York against Texas oil billionaire Sid Bass and his wife, Althea Viafora Bass.

The documents include the case docket as of October 8, as well as Sperr's 98-page complaint. The complaint includes 18 figures: a shared calendar, Bass's paintings, Christmas cards, a jewelry receipt, a Christie's catalog image and the August 22, 2025, email announcing the marriage.

Next is Viafora Bass's October 8 motion to dismiss and her 30-page memorandum of law, filed by Paul Hastings. The memorandum recounts her career as a gallerist, Hauser & Wirth associate director, and Sotheby's Institute of Art instructor.

Also included is Viafora Bass's October 6 motion to change the case caption to her married name, which Abrams granted on October 7. Attached are a lawyer's declaration, the couple's Aransas County, Texas, marriage license and her redacted Texas driver's license.

The set also includes both defendants' requests for more time to respond, which Abrams granted, along with notices of appearance by Bass's lawyers at Latham & Watkins, the court's order setting an October 30 initial conference, and the summonses issued to Bass and Viafora Bass.

Read the story: Sid Bass and his gallerist wife move to toss ex-partner's $400 million suit

Sid Bass and gallerist wife move to toss ex’s $400M suit

Her complaint accuses Viafora Bass, 68, of “grooming” Bass.

Urgent MatterAdam Schrader