Shares have eased from record peaks as optimism about a global economic recovery was dented by caution before a policy decision by the Federal Reserve and earnings updates from a number of blue-chip companies.
The MSCI world equity index, which tracks shares in 49 countries, fell 0.1 per cent by 1040 GMT on Tuesday, following a muted session in Asia and slight losses in Europe.
The world index has risen 9 per cent so far this year, underpinned by expectations that rising COVID-19 vaccination rates will allow more economies to recover and give a big boost to company profits.
Earnings in Europe are expected to have risen 61 per cent in the first quarter, while US profits are seen up more than 31 per cent, according to the latest Refinitiv IBES estimates.
Many investors however stayed on the sidelines ahead of the Fed meeting that ends on Wednesday, when the US central bank is expected to confirm that it will maintain its easy monetary policy to bolster the economy.
One area of concern was India, which is struggling with surging coronavirus infections that have overwhelmed its healthcare system.
Markets were also awaiting for results from US tech heavyweights Microsoft and Alphabet later on Tuesday. Companies that represent about 40 per cent of the S&P 500's market capitalisation report from Tuesday through Thursday.
"There are yet to be any real punctures in the global risk balloon at the moment," wrote Deutsche Bank strategist Jim Reid. "We'll have to wait and see if these upcoming events might throw this off course."
Some analysts say the recent rally has made stocks vulnerable to profit taking, given lofty valuations and high expectations going into the reporting season.
In pre-market trade, Tesla shares fell more than 2 per cent even after the electric car maker beat Wall Street expectations for first-quarter revenue.
S&P 500 and Nasdaq futures both rose less than 0.1 per cent. Earlier the MSCI's broadest index of Asia-Pacific shares outside Japan ended little changed.
In Europe, bank results grabbed the attention. Strong earnings sent shares in Europe's biggest bank by assets HSBC up 2.6 per cent, while UBS fell after a surprise hit linked to the collapse of hedge fund Archegos.
Copper prices hit a 10-year high, climbing closer to their record peak as supply worries in top producer Chile added to hopes for an improvement in global demand amid a stable economic recovery.
Benchmark copper on the London Metal Exchange was up 1.5 per cent at $US9901 a tonne at 1110 GMT, a gain of 27 per cent this year.
Oil rebounded as optimism ahead of a meeting of producer group OPEC+ to discuss output policy offset concern that India's coronavirus crisis could dent a recovery in fuel demand.
Brent crude was 0.6 per cent up at $US66.03 a barrel and US oil gained 0.7 per cent to $US62.35.
The dollar hovered near multi-week lows versus major peers but moves were narrow as traders avoided taking out big positions before a bond auction and the Fed meeting.
After rising as much as 0.25 per cent it pared gains to trade flat on the day at 90.899.
"Nobody really believes that the Fed will change its forward guidance, but just in case, investors appear to be loading up on US dollar as a hedge," said OANDA analyst Jeffrey Halley.
Bond traders were closely watching an auction of $US62 billion of seven-year US Treasuries later on Tuesday.
The Treasury saw very weak demand at a seven-year debt auction in February, which sparked a brutal global selloff. The notes also saw tepid, although improved, demand in March.
Ahead of the auction results, seven-year US yields edged up to 1.2736 per cent, while benchmark 10-year yields rose slightly to 1.5827 per cent.
The yen fell 0.2 per cent from a seven-week high against the dollar after the Bank of Japan kept policy on hold as widely expected and said it was ready to extend its pandemic relief program.
Bitcoin rose 1.3 per cent to $US54,770. The world's most popular cryptocurrency soared nearly 10 per cent on Monday, after five straight days of losses, on reports that JPMorgan Chase is planning to offer a managed Bitcoin fund.
Bitcoin had slumped almost a fifth from an all-time high hit this month.