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

The new wife of Texas oil billionaire Sid Bass, a former SoHo gallerist, asked a federal judge in Manhattan on October 8 to dismiss the $400 million lawsuit Oona Sperr filed against the couple. Sperr says she lived with Bass for a decade.

"Plaintiff Oona Sperr's lawsuit against Althea (and her husband Sid Bass) asserts frivolous claims that the New York legislature effectively abolished nearly a century ago," lawyers for Althea Viafora Bass at Paul Hastings wrote.

Bass, 84, filed his own motion to dismiss the same day. Both defendants requested oral argument before U.S. District Judge Ronnie Abrams.

Sperr, 64, an interior designer, sued in August. She alleges Bass broke an oral agreement made in Manhattan in 2014 to share his homes with her and support her for life in return for her giving up her career to run his households.

Her complaint accuses Viafora Bass, 68, of "grooming" Bass and steering him away from those promises. It says this happened as Bass's cognition and judgment declined from excessive alcohol consumption and early signs of Parkinson's.

Viafora Bass's brief says she opened the Althea Viafora Gallery in the 1980s and operated it from several Manhattan spaces until the early 1990s. She later worked as an associate director at Hauser & Wirth and taught gallery business, collection building, and art advisory at Sotheby's Institute of Art, including its art business master's program with Tsinghua University.

The gallery gave painter Elizabeth Peyton her first solo exhibition in 1987, Sotheby's wrote in its catalog note for Peyton's Portrait of Althea Viafora, offered in a 2019 sale.

New York Times critic Roberta Smith reviewed a Verne Dawson show at the gallery's 578 Broadway space in October 1989, a clipping posted by Karma shows.

Paid subscribers can read the documents used in this reporting.

Court Documents: Oona Sperr’s $400M lawsuit against Sid Bass

Court documents from Sperr v. Bass in the U.S. District Court for the Southern District of New York.

Urgent MatterAdam Schrader

The brief says Viafora Bass stepped back from the gallery in the early 1990s to care for Peter Jay Sharp, the developer she had been with for years. It says Sharp introduced her to Bass in the early 1980s.

Sharp, who owned the Carlyle hotel and was a trustee of the Metropolitan Museum of Art and the Juilliard School, died of melanoma in April 1992, his Princeton Alumni Weekly memorial shows.

The brief says romance followed an invitation from Bass to visit him in Colorado. The two married on August 9, 2025, on San José Island, the Bass family's private island off the Texas Gulf Coast.

Sperr's complaint tells it differently. It calls Viafora Bass "a woman who has spent her adult life seeking proximity to well-connected, rich men with famous families, and who describes herself in recently updated online profiles as an 'Artist's Studio Advisor.'"

The complaint says she had been "pursuing Sid since late 2022 under the pretext of seeking advice on how to invest a few hundred thousand dollars she recently inherited." It says that pursuit included a lunch with Bass and Sperr at Tacombi on the Upper East Side that December.

"To be clear: Plaintiff's allegations are false," the brief says. It says Viafora Bass is financially independent and that the advice she asked Bass for "concerned her own money."

"Were this case to enter discovery, Plaintiff's allegations not only would be proven false, but also would be subject to sanctions," the brief says.

The two sides have also fought over her name. The complaint calls her Althea Irene Viafora Kress, says she "now purports to be Sid's wife," and calls the marriage a "sham" ceremony.

On October 6, her lawyers asked to change the case caption, saying the complaint used her former name "in an apparent attempt to cast aspersions upon her marriage." Abrams granted the request the next day.

The motion attached the couple's Aransas County, Texas, marriage license and her Texas driver's license. It says she uses the Bass name publicly "in connection with her professional work in art advising, teaching, and advocacy."

The complaint says Sperr learned of the wedding from an email sent from Bass's account on August 22, 2025. "Althea and I were married on Saturday, August 9th at San Jose Island," it reads. "Althea will change her name to Viafora-Bass."

The complaint alleges that Viafora Bass wrote the email herself.

Viafora Bass's legal argument starts with New York's 1935 "anti-heart balm" law, which ended lawsuits over alienation of affection and broken engagements. The brief says suits by "purportedly heartbroken lovers" are, in a 1950 state court decision's words, "commonly the vehicle for fraud and extortion."

The brief also relies on a 1980 Court of Appeals ruling that rejected implied contracts between unmarried partners, though Sperr's complaint pleads an express agreement. It argues New York law requires any promise of lifelong support or a share of real estate to be in writing.

"If Plaintiff and Sid wanted the law to recognize their purported 'lifelong partnership' or for the law to infer 'injustice' in the absence of community property to Plaintiff following the end of that relationship, then Plaintiff and Sid could have gotten married," the brief says.

It says Sperr gives "no explanation for how, exactly, Plaintiff derived that gobsmacking number," meaning the $400 million.

The brief says "the few facts Plaintiff alleges at most establish that Althea married the man she loves."

Sperr's 98-page complaint, filed August 31 by Kaplan Martin, says she met Bass in 1995 on an American Academy in Rome trip to Italy, when he was married to his second wife, Mercedes Bass.

The complaint says the two ran into each other again at Sotheby's in December 2011. In January 2014, over lunch at his East 94th Street townhouse, Bass allegedly asked her, "How about you never leave?"

Sperr gave up her interior design career, the complaint says, and ran homes on East 70th and East 71st streets in Manhattan, a combined loft in Fort Worth and a 7,000-acre ranch in Pagosa Springs, Colorado.

The complaint says that on September 3, 2024, at the ranch, Bass told her, "I want a separation. You are to pack and leave."

Bass initially offered $50 million, the East 71st Street house, a second home, and continued care for Sperr's 96-year-old mother, the complaint says.

A "Maintenance Agreement" his lawyers sent in January 2025 offered $5 million a year through January 2035 and a lifetime lease instead of ownership, the complaint says. The agreement also included "sweeping, one-sided non-disclosure" terms.

Sperr also asks the court to hold the two Manhattan houses, the Fort Worth loft, and the Colorado ranch in trust for her and to order an accounting of any assets that went to Viafora Bass.

The complaint says the couple's New York social life "centered in many respects around the Museum of Modern Art." Bass currently serves on the MoMA board with Leon Black, a former associate of Jeffrey Epstein, whose townhouse was also on East 71st Street.

Bass "secured institutional privileges for Oona reserved for spouses by obtaining a card for Oona that identified her as a MoMA Trustee (which she is not)," the complaint says.

He also got her a card at the Met, a Sotheby's Preferred card in his name, and family memberships at the Guggenheim and the Amon Carter Museum, the complaint says. Around 2016, Alice Tisch, then chair of MoMA's Design Committee, invited Sperr to join the committee.

The complaint says Bass's homes hold works by "Matisse, Picasso, Van Gogh, Rothko, and Warhol." The couple's Manhattan bedroom held a Van Gogh "that art dealer and gallerist Bill Acquavella valued at $150 million." The complaint does not name the painting.

Sperr picked a Léger and a Guillaumin from Bass's parents' collection for the couple to keep during their lives, the complaint says. Christie's sold 36 works from that collection in November 2017, led by Van Gogh's Laboureur dans un champ, CultureMap reported.

Around March 2016, Sperr discovered major pieces missing from Nancy Lee Bass's jewelry collection. A family investigation "revealed that two members of the Bass security staff had stolen more than $5 million worth of jewelry from Nancy Lee Bass's house" after Perry Bass died, the complaint says.

It says the pieces were sold through Sotheby's, which had been hired to catalog the collection for her estate.

When the family asked about a Harry Winston diamond necklace valued at $1.2 million, "Sotheby's denied selling the piece and claimed the photograph from their catalogue was not an exact match," the complaint says. The family did not sue.

The complaint also alleges that decorator Leta Austin Foster, hired by Ramona Bass to redo the San José Island house, stole furniture from the house's 1980s redecoration and "overcharged the family by more than $2 million for fabrics." The family took no action.

The complaint says Bass, while still married to Mercedes Bass, had an affair with another woman. He later offered her "a Rodin sculpture valued at over $1 million," and furniture bought at auction, under agreements meant "to secure her silence regarding the affair."

The couple toured the former Knoedler & Company gallery building, which Black bought, before settling on a 12,000-square-foot house on East 70th Street once owned by Condé Nast publisher Si Newhouse "to display his vast art collection," the complaint says.

The complaint says Bass "had long dreamed of becoming an artist" before family obligations put him in charge of the Bass businesses. Bill Bomar of the Fort Worth Circle, Sperr's step-uncle, encouraged his early drawings.

One night in Chelsea, the complaint says, Sperr met Bass under the High Line, where "Sid, disguised in a workman's vest and hard hat, was walking away from his freshly painted mark on 23rd Street." After the pandemic, Bass "had all but stopped painting."

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