The top 25 employees at each firm had their pay limited in October

The White House "pay czar" has extended limits on the pay of executives at four US firms who were given government bailout money.

Under the restrictions, announced by Kenneth Feinberg, employees will not be able to earn more than $500,000 (£307,770) per year.

The rule refers to the 26th to 100th highest paid staff. The top 25 at each firm had their pay limited in October.

The companies involved are Citigroup, AIG, General Motors and GMAC.

The ruling does not apply to Bank of America because it repaid its bailout money this week, and Chrysler and Chrysler Financial were exempted because total pay for their second-tier executives is already under $500,000.

The new rules will not affect what the employees involved have already been paid this year but will affect many workers' year-end bonuses and stock grants, Mr Feinberg said.

Mr Feinberg is in charge of the executive compensation for the Troubled Asset Relief Program (TARP), which is the US government's aid programme for banks, financial institutions and other large companies.