The director of the office of municipal securities at the Securities and Exchange Commission, John Cross, will leave his post in November to return to the U.S. Treasury Office of Tax Policy, the agency said on Tuesday.

Cross was named head of the newly formed office barely two years ago after becoming a leading figure in the $3.7 trillion municipal bond market through his role as associate tax legislative counsel in the Treasury's tax policy arm.

"As the Office of Municipal Securities' first director, John provided valuable leadership and expertise in the oversight of the municipal securities market that is so vital to financing our public infrastructure," said SEC Chair Mary Jo White, in a statement.