May 11 (Reuters) - The Obama administration and senior congressional Democrats are moving to tighten U.S. financial regulation to prevent another banking crisis. Changes will affect banks, insurers, credit rating agencies, hedge funds, private equity firms, brokerages and exchanges while greatly extending the government's reach into the financial sector.

Here are the major issues:

CREDIT CARDS

The U.S. House of Representatives and a Senate committee have approved bills to crack down on credit card companies by, for example, limiting fees and barring sudden rate increases.

The House approved its bill by a vote of 357-70 on April 30. Debate on the Senate bill is expected to begin soon.

Political risk exposure: American Express (AXP.N: Quote, Profile, Research), Bank of America (BAC.N: Quote, Profile, Research), JPMorgan Chase (JPM.N: Quote, Profile, Research), Capital One (COF.N: Quote, Profile, Research), Citigroup (C.N: Quote, Profile, Research), Discover Financial (DFS.N: Quote, Profile, Research).

HOUSING, MORTGAGES AND SECURITIZATION

The Senate and the House are moving closer to agreement on legislation to tighten rules on mortgage financing, curb predatory lending and assist troubled homeowners.