Oona Sperr, 64, has filed a $400 million lawsuit against billionaire oil heir Sid Bass, 84, alleging he abruptly ended their 10-year relationship in September 2024 with a curt dismissal and subsequently married socialite Althea Irene Viafora Kress, 68. The lawsuit, filed in federal court, claims Bass was “groomed” by Kress over a two-year period before he ended his relationship with Sperr.
According to the suit, the breakup occurred at their 7,000-acre ranch in Pagosa Springs, Colorado, during their usual breakfast of dairy-free yogurt and berries. Bass allegedly told Sperr, “I want a separation. You are to pack and leave.” Sperr, blindsided by the statement, questioned Bass about the possibility of another woman, citing his “well-known history of cheating on his previous wives.”
Bass reportedly denied infidelity and offered Sperr $50 million, a New York City home, and another residence of her choice to leave quietly. However, while Sperr was clearing her belongings, she allegedly overheard Bass referring to Kress as “sweetheart,” a term he had previously reserved for Sperr.
Sperr’s lawsuit claims Kress then directed Bass to sever all contact with Sperr, remove her possessions from their properties, and even instructed him not to drive Sperr to the airport. The lawsuit also states that Bass had suffered three mini-strokes and had been diagnosed with Parkinson's disease at the time of the separation, and Sperr accuses Kress of taking advantage of his alleged cognitive decline.
Bass and Kress married on Bass’s private Texas island in August 2025. Sperr claims she was only notified of the wedding two weeks later via an email from Bass. The email, which Sperr suspects was actually written by Kress, stated: “Althea and I were married on Saturday, August 9th at San Jose Island. Hyatt, Samantha and grandsons, plus Lee and Ramon attended. Althea’s seven closest friends attended.”
Sperr described her decade-long relationship with Bass as “loving” and “committed.” They first met in 1995 in Rome while Bass was married to his second wife, Mercedes Tavacoli Kellogg Bass. The lawsuit details Bass’s previous marriages, including his divorce from his first wife, Anne Hendricks Bass, in the late 1980s, which was reportedly one of the decade's high-society scandals and resulted in a $200 million to $500 million settlement. His divorce from Mercedes in 2011 also included significant financial settlements.
Sperr alleges that Bass confided in her after his divorce from Mercedes, expressing a desire to step away from high-society life and focus on painting. She claims to have managed their shared properties, including a $26 million townhouse in Manhattan and numerous estates across Colorado and Texas, as well as overseeing renovations and staff. Sperr stated that she was drawn to Bass's artistic side rather than his wealth and that their relationship included gestures of commitment, such as a 25.6-carat diamond ring and a 20-carat emerald, along with her appointment as power of attorney for his affairs and health care proxy.
Bass and Sperr reportedly lived a life of luxury, traveling on Bass's Gulfstream jet and residing in homes filled with art by masters like Van Gogh, Monet, and Picasso. Sperr’s lawsuit also mentions that the couple experienced harassment from Patricia Zohn Pfeiffer, a former lover of Bass with whom he allegedly had an affair while married to Mercedes.
Roberta Kaplan, Sperr’s attorney, stated that the case is about broken promises, emphasizing that Sperr abandoned her career and cared for Bass through illnesses, expecting him to fulfill his commitment to provide for her and her mother. The lawsuit further alleges that Bass attempted to silence Sperr with non-disclosure agreements and that Kress intentionally interfered with their relationship, causing the alleged damages. Bass and Kress have not yet filed a response to the suit.