Rosalind Ramsey Tyson, director of the U.S. Securities and Exchange Commission’s Los Angeles regional office, will retire at the end of March after 30 years with the regulatory agency.

Tyson, 63, has led the 170-person office since 2007, and oversees enforcement and examination activities in Southern California, Arizona, Nevada and Hawaii.

Among the high-profile cases the office has pursued under her leadership include the filing of several civil charges related to the subprime mortgage meltdown against former Countrywide Chief Executive Angelo Mozilo and former executives with defunct lenders IndyMac and New Century Financial Corp.

The SEC in its announcement did not say who would succeed Tyson in the post.

“Thirty years ago, Roz answered the call of public service and dedicated her career to protecting investors and maintaining the primacy of our capital markets,” said SEC Enforcement Director Robert Khuzami in a statement.