The S&P 500 traded just below a record high of 4249.74, with heavyweight technology stocks serving as the largest boost.

Sectors such as financials and basic resources that stand to benefit from an economic bounceback this year also supported the index.

Investors scaled back expectations for early policy tightening by the Fed after May's consumer price data suggested a recent spike in inflation would be transitory.

Much of the price surge in May came from items such as commodities and airfares, and it is expected to be temporary.

With recent data also indicating weakness in the labour market, the Fed is widely expected to maintain accommodative policy at its meeting next week, which is positive for stocks and other risk-driven assets.

"The commentary will be that they're still focusing on the last two employment reports, which were much weaker than anticipated," Sam Stovall, chief investment strategist at CFRA Research in New York, said.

"And so the Fed will have to wait for additional data before even talking about tapering.

"This meeting coming up, plus the meeting in late July, will probably result in no policy changes, or even contemplation of policy changes."

At 9.45am Eastern Time, the Dow Jones Industrial Average was up 87.44 points, or 0.25 per cent, at 34,553.68; the S&P 500 was up 6.54 points, or 0.15 per cent, at 4245.72; and the Nasdaq Composite was up 19.12 points, or 0.14 per cent, at 14,039.46.

The S&P 500 and the Nasdaq were set for mild weekly gains, as a lack of major catalysts and a summer lull in trading saw them move in a tight range.

But weakness in major industrial stocks saw the Dow Jones set for a weekly loss amid doubts over whether President Joe Biden's $US2.3 trillion infrastructure spending plan would pass.

The S&P industrials sector rose 0.4 per cent on Friday, but was set to lose for the week.

Cruise operators fell in early trade, with Royal Caribbean Group shedding 1.6 per cent after two guests on its Celebrity Millennium ship tested positive for COVID-19.

Stocks favoured by small-time retail investors that have dominated trading volumes in recent weeks were set to close higher for the week, even as a rally appeared to be running out of steam on Thursday.

Most of the so-called 'meme' stocks rose on Friday.

Advancing issues outnumbered decliners by a 2.17-to-1 ratio on the NYSE and a 1.90-to-1 ratio on the Nasdaq.

The S&P index recorded 18 new 52-week highs and one new low, while the Nasdaq recorded 50 new highs and six new lows.

Australian Associated Press