* Hoyer expects House approval on Wednesday

* Citigroup, Bank of America among those affected

* Coburn gun rights amendment tacked onto bill (Adds Hoyer, Geithner comments, background, stock prices)

By Kevin Drawbaugh

WASHINGTON, May 19 (Reuters) - The U.S. Senate on Tuesday voted 90-5 to approve a bill to curb sudden credit card interest rate increases and hidden fees, with President Barack Obama expected to sign it into law by the end of the month.

Credit card issuers' shares fell after passage of the bill, the first of several banking and market regulation reforms expected from the Obama administration as it deals with the worst financial crisis in generations and a deep recession.

The credit card "consumer bill of rights," as supporters describe it, must go to the U.S. House of Representatives for a vote before reaching the president. The House approved it in a very similar form last month by a 357-70 vote. (For a FACTBOX on major US financial regulation initiatives, please double-click: [ID:nN19438886])

House Democratic Leader Steny Hoyer told reporters on Tuesday: "We expect to pass (the bill) by sometime tomorrow, the earlier the better ... My expectation is that we will send that bill directly to the president from the House."

Analysts said the profits of major card issuers such as Citigroup (C.N: Quote, Profile, Research), Bank of America (BAC.N: Quote, Profile, Research), JPMorgan Chase (JPM.N: Quote, Profile, Research) and Capital One (COF.N: Quote, Profile, Research) would be hurt by the bill.