Rep. Christopher Cox (search) was sworn in Wednesday as chairman of the Securities and Exchange Commission, taking the oath from Federal Reserve Chairman Alan Greenspan (search), the SEC said in a statement.

Cox, R-Calif., is expected to begin work at the investor protection agency Thursday. He plans to speak to the SEC staff Thursday morning.

Cox was White House liaison to the SEC for President Ronald Reagan (search) when he first met Greenspan, the statement said.

A congressman since 1988, Cox was nominated to head the SEC by President Bush in June and confirmed by the Senate last month.

He replaces William Donaldson (search), who resigned on June 30 after a little over two years on the job.

The Securities Industry Association (search), which represents Wall Street brokerages, praised Cox in a statement and urged him "to consider less costly regulation, more balanced supervision and uniform national and international standards."