Greta Beer, whose struggles to recover her family’s savings led to a lawsuit against Swiss banks, dramatic testimony before a congressional committee and a settlement of more than $1 billion for families whose assets were lost during the Holocaust, died Jan. 23 at a retirement facility in Brighton, Mass. She was 98.

The cause was a kidney ailment, said her friend and executor, Doina Simovici.

Mrs. Beer grew up in Romania before World War II as part of a wealthy, cosmopolitan Jewish family. Her father, Siegfried Deligdisch, owned a textile factory, and Mrs. Beer was educated at a French-language boarding school in Switzerland.

Just as Europe was becoming engulfed in war, her father became ill with kidney disease. He assured his wife and two children that he had put aside plenty of money for them in a Swiss bank account.

“He would always say, ‘Don’t worry kids, it looks dark, the war is imminent, but you are provided for, no matter what happens,’ ” Mrs. Beer told the Associated Press in 1998. “My father believed in Switzerland, it was a neutral country.”

She was with her father as he sought treatment at a hospital in Budapest, but his illness worsened, and he died in September 1940 without revealing the account number or even the name of the Swiss bank where he said the money was deposited.

Mrs. Beer, her mother and brother returned to Romania and eventually made their way to the small city of Brasov in the Carpathian Mountains, where they were sheltered by Christian friends.

As Soviet forces began to overrun Romania near the end of the war, Mrs. Beer fled to Hungary, then to Austria, leaping from a train before being smuggled through the countryside in a truck carrying contraband, she told friends. While living in a facility for displaced people in Vienna, she married Simon Beer, a doctor.

They later lived in Italy before entering the United States in 1951, classified as stateless refugees. Mrs. Beer became a U.S. citizen in 1956. (In a U.S. passport application, she explained that she had “lost my nationality of origin” because she was “fleeing from Roumania.”)

Her mother later settled in Switzerland, and together they began to search for the family fortune. They went to dozens of banks in Zurich and Geneva, but in every case they were told that no records could be found.

Beginning in the 1960s, some Swiss banks made efforts to return money to families whose lives were disrupted by the Holocaust, but thousands of claims, including Mrs. Beer’s, were denied.

In the 1990s, an independent commission under the direction of Paul A. Volcker, a former chairman of the U.S. Federal Reserve, launched an investigation of Swiss banking practices. Although many documents had been destroyed, the commission identified more than 50,000 accounts held by Holocaust victims. Swiss banks had claimed there were fewer than 1,000 such accounts.

“The banks had no incentive to find out the truth about the assets because they felt they should protect the honor of Switzerland,” Volcker told The Washington Post in 1999. “They could have solved this problem a long time ago if they really wanted to.”

At the same time, the Swiss government asked a group of historians to examine the country’s actions during and after World War II. The historians concluded that major Swiss banks had blocked efforts by families to retrieve their missing funds and had charged exorbitant fees to anyone seeking information about closed or inactive accounts.

In a 1995 Wall Street Journal article, Mrs. Beer became the public face of Jewish families seeking restitution. Her plight soon drew the attention of Stuart E. Eizenstat, who held several high-profile positions under President Bill Clinton and became the administration’s special representative on issues related to the Holocaust.

“Her story of the rude treatment she received from Swiss bank executives in trying to locate her late father’s World War II-era bank account made her the symbol for victims in the Swiss bank affair,” Eizenstat wrote in his 2003 book “Imperfect Justice: Looted Assets, Slave Labor and the Unfinished Business of World War II.”

“Her life became a metaphor for all those Jews whose families had trusted their secretive bankers in Zurich and Geneva and were betrayed by them.”

Mrs. Beer filed suit against Swiss banking groups and later joined a class-action lawsuit. In 1996, when the Senate Banking Committee conducted hearings on the matter, she was the first witness.

“May I just say,” she testified, “in this conflagration — in this unbelievable hell around us, this was a safe haven, this was a bastion you looked to, it was a star in the sky: Switzerland.”

The resulting controversy involving the powerful Swiss banks “would roil Swiss-U.S. relations as no other incident in our 140-year-long diplomatic relationship,” Eizenstat wrote in his book. “What began as a simple investigation into dormant bank accounts turned into a diplomatic debacle, forcing Switzerland to reexamine its role as a neutral nation.”

Grete Georgia Deligdisch was born June 25, 1921, in Cernauti, Romania. (The city, which once had a substantial Jewish population, was also known by its German name, Czernowitz. It is now the Ukrainian city of Chernivtsi.)

Young Grete — who changed the spelling of her first name after coming to the United States — attended schools in Romania and Switzerland, studied piano and spent summers in Italy. She was fluent in six languages: Romanian, German, Italian, French, English and Polish, her mother’s native language.

While living in Milan in the late 1940s and early 1950s, Mrs. Beer attended the La Scala opera house several times a week and remained a devoted opera lover throughout her life. She settled in New York, where she held secretarial jobs and worked, at different times, at the Museum of Modern Art and Metropolitan Opera.

She traveled frequently and became a tour guide, leading multilingual sightseeing groups in New York and Washington. She was divorced in 1969 and had lived in Massachusetts for about 20 years. She had no immediate survivors.

After the Senate hearings and an accompanying self-reckoning on the part of the Swiss, Eizenstat helped negotiate an out-of-court financial settlement of $1.25 billion with the Swiss banks. U.S. District Judge Edward R. Korman oversaw the distribution of the funds to Holocaust victims and their heirs who were part of the class-action suit.

“I hope some justice will be done for us,” Mrs. Beer told the judge at a hearing in 1999. “We have fought for many, many years. In the name of my father, I do hope.”

In the end, she was never able to prove that her father held an account with a Swiss bank. Nevertheless, when Korman began to disburse the money from the Swiss banks in 2002, the first check, in the amount of $100,000, went to Mrs. Beer “in recognition of her services” to victims of the Holocaust.