Cynthia Glassman (search), the senior Republican member of the Securities and Exchange Commission (search), has been designated acting SEC chairman, the White House said in a statement on Thursday.

William Donaldson (search) has stepped down as SEC chairman and President Bush has said he will nominate Republican California Rep. Christopher Cox to replace him. But Cox's nomination has not yet been formally transmitted to the Senate for review.

"I'm honored that the president has designated me to be acting chairman and I look forward to welcoming Chris Cox as our permanent chairman pending his confirmation," Glassman told Reuters.