The NYSE itself insisted on a new condition before considering Siebert's application. It insisted that Siebert obtain a letter from a bank offering loans of $300,000 at the near-record $445,000 seat price. But banks would not commit to lending her the money until the NYSE would agree to admit her. Siebert finally was elected to membership on December 28, 1967. In 1975, when the Securities and Exchange Commission first permitted broker commissions to be negotiable, she criticized the discount brokers vehemently; she ran numerous ads calling the discounters and the rates "low ball". In 1977, she was named Superintendent of Banks for the State of New York, with oversight of all of the banks in the state, regulating about $500 billion. Not one bank failed during her tenure, despite failures nationwide. When she learned Hugh Carey, New York Governor at the time, had appointed her to the position, Siebert recalled thinking, "Mickie, you know you're a college dropout. You've done pretty well as a college dropout!"