NEW YORK (AFP) - Wall Street stocks finished mixed ahead of a Federal Reserve announcement expected to shine light on the central bank's thoughts on future interest rate hikes.

The Dow Jones Industrial Average dropped 0.3 per cent to 26,492.34.

The broad-based S&P 500 shed 0.1 per cent to 2,915.58, while the tech-rich Nasdaq Composite Index gained 0.2 per cent to 8,007.47.

Analysts view the Fed as almost certain to lift interest rates again on Wednesday but are watching for the US central bank's outline of additional interest rate hikes down the road.

US economic data remains good, with the Conference Board reporting a jump in consumer confidence in September to a near-18-year high.

Analysts told AFP the central bank was unlikely to signal a change in the pace of interest rate increases but that this could change in the near term, as policymakers take a more hawkish view of trends in inflation.

"They are going to raise rates in September and probably going to give the signal that they going to raise rates in December," David Wessel of the Brookings Institution, told AFP.

"Where it gets interesting, and there is a lot of uncertainty, is what happens after that." Among individual shares, General Electric plummeted 4.1 per cent on lingering questions about its prospects following a glitch with electricity turbines that temporarily led to outages at two plants in Texas.

Michael Kors Holdings rose 2 per cent after announcing it was buying Italian fashion house Versace for US$2.1 billion (S$2.8 billion) and saying it would rename itself Capri Holdings.

Fast food chain Sonic surged 18.7 per cent after announcing it agreed to be bought by Inspire Brands for US$2.3 billion.