Broker-dealers and FCMs are required to maintain certain minimum amounts of regulatory capital in order to stay in business. Historically, so long as a firm maintained the required level of capital, it was free to withdraw any excess. However, in 1990, the parent company of Drexel Burnham Lambert, Inc. ("Drexel"), a registered broker-dealer, came into severe financial pressure as a result of its improper financial activities. In an ultimately failed attempt to save itself, Drexel's parent holding company withdrew virtually all the excess regulatory capital from Drexel, turning Drexel overnight from a well-capitalized firm into one that had barely more capital than was legally required to operate. In response to this, the SEC soon after adopted rules that prevented a firm from quickly sending any significant amount of capital away to its affiliates without obtaining advance regulatory approval. The SEC's rule-change was then imitated by other regulators and applied to entities other than SEC-registered broker-dealers.