A Federal Reserve decision to boost interest rates would give a lift to large US banks and offset the drag on earnings from legal settlements and toughened regulations.

If the Fed gives the green light to a rate hike Thursday, JPMorgan Chase, Bank of America and other large banks would charge more on loans to businesses and individuals, affecting myriad transactions, from car purchases to mortgages, to business capital investment.

"Lending money is going to be profitable again," said Gregori Volokhine, president of Meeschaert Capital Markets.

Banks would also view a Fed rate hike as a boost to the economic outlook and a "green light" to increase overall lending levels, he said.

After a two-day meeting, the Fed on Thursday at 1800 GMT will release a monetary policy statement, followed by a news conference with chair Janet Yellen.

Fed officials have signalled plans to lift rates in 2015, but some analysts think a move Thursday has become less likely due to turbulence in global markets. If the Fed does lift rates, it would be the first increase since 2006.

An increase in their loan rates of one percentage point would translate into $2.70 billion in additional profits for JPMorgan, $3.85 billion for Bank of America and about $2 billion for Citigroup, according to calculations included in the banks' securities filings.

But if the Fed does move on rates this week, the hike is likely to be just 0.25 percent, which on its own would not significantly boost bank profits.

"If they only increased it 25 basis points, I think the banks will welcome the signal, but you are not going to see massive earnings improvement on something like that," said Justin Fuller, a senior director at Fitch.

"In order for them to benefit from increased interest rates, they need a series of rate increases over time."

Analysts say banks could receive an additional benefit from an interest rate hike this week if businesses hasten efforts to secure debt financing in advance of subsequent increases.

"You will see some kind of more rapid borrowing to get in before rates go up further," Fuller said.