(Reuters) - JPMorgan Chase & Co has the ability to repurchase $950 million of its own shares, under an authority previously approved by the Federal Reserve.

The second largest U.S. bank didn't spend as much as it was allowed on dividends and can instead use the money to buy back stock and warrants, Chief Executive Officer Jamie Dimon said at a Goldman Sachs investor conference in New York on Wednesday.

The bank has the ability to start buying back stock right away but will decide what to do over time, Dimon said.

JPMorgan repurchased $4.4 billion in shares during the third quarter.

Dimon also provided an update on the bank's fourth-quarter and 2012 outlook.

JPMorgan expects investment banking income to be relatively flat in the fourth quarter compared with the third quarter, excluding an accounting adjustment, according to Dimon's presentation. The bank also expects low interest rates to reduce 2012 net income by about $400 million.