(Reuters) - American Express Co, the No. 4 U.S. credit card issuer, is seeking about $3.5 billion in tax-payer funded capital from the U.S. government, the Wall Street Journal said, citing people familiar with the situation.

It was not clear if the application under the Troubled Asset Relief Program (TARP) came before or after the company got Federal Reserve approval to become a bank-holding company.

American Express has not announced the application, and it is not known how it would use government money, the paper said.

The company won the approval of the Federal Reserve Board to become a bank holding company on Monday.