American business executive whose successful ventures in the realm of high finance helped expand opportunities for women in that field.

Siebert attended Western Reserve University in her hometown from 1949 to 1952 but did not complete a degree. In 1954 she moved to New York City, where, over the next six years, she worked as an analyst at three financial services companies. After serving as a partner at three others, she became in 1967 the first woman to buy a seat on the New York Stock Exchange. Shortly thereafter, in 1969, she formed her own discount brokerage firm, Muriel Siebert & Co., Inc. In 1977 she became the first woman superintendent of banking for the state of New York. At the same time, she served as director of New York City's Urban Development Corporation and Job Development Authority (both from 1977 to 1982). She resigned in 1982 to run for the U.S. Senate. After losing the election she returned to her own company, where she was chairman and president from 1983. She was inducted into the National Women's Hall of Fame in 1994.