(Reuters) - Muriel Siebert, the first woman to own a seat on the New York Stock Exchange, has died of complications from cancer, Leonard Leiman, a director at her firm Siebert Financial Corp., said on Sunday. She was 80.

The founder and president of Muriel Siebert & Co. Inc, Siebert purchased her seat on the exchange in 1967, nearly a decade before the next woman would join her there.

Despite credentials including partnerships at two leading brokerages and the founding of her namesake firm, Siebert's initial attempt to gain a seat on exchange was met with sharp opposition and even ridicule by much of its all-male membership, according to her official biography on her company's website. She eventually prevailed.

Known as "Mickie," Siebert made another bold move in 1975, transforming her firm to into a discount brokerage on the first day that New York Stock Exchange members were allowed to negotiate their commissions.

"Mickie was a pioneer and recognized as a leader throughout the financial services industry and beyond," Joseph Ramos, Siebert Financial's chief operating officer, said in a statement. "She was respected as a strong voice of integrity, reason and sound business practices."

Siebert later became the first woman to serve as Superintendent of Banking for the State of New York, accepting the appointment by Governor Hugh Carey in 1977.

An outspoken champion of women and minorities in industry and government, Siebert made an unsuccessful run for the U.S. Senate in 1982, losing in the Republican primary to state lawmaker Florence Sullivan.

Sullivan went on to lose to Daniel Patrick Moynihan.