A raft of better-than-forecast earnings results for US corporate giants had catapulted New York's S&P 500 and tech-heavy Nasdaq indices to all-time peaks on Tuesday, while the Dow Jones Industrial Average came close.
However the surge failed to translate into significant gains in markets around the globe, and some less positive results on Wednesday led to cautious trading at midday on Wall Street.
Among the disappointments were Caterpillar and Boeing, which said the global grounding of its 737 MAX planes -- sparked by two deadly crashes -- would cost $1 billion.
The US planemaker also reported lower profits, but its share price still rose by 0.7 percent, likely due to relief that the damage was not worse.
Briefing.com analyst Patrick O'Hare wrote that investors might also be hesitant due to disappointing economic news out of Germany and Australia.
"The bigger takeaway, however, is that sellers are still the reluctant bunch," he wrote.
- 'Feelgood factor' fades -
Oanda analyst Craig Erlam said that while Tuesday saw a batch of positive results, "it's not yet clear whether it's an outlier or a sign of what's to come".
"The boost has only been seen domestically and even here, the feelgood factor has already faded," Erlam told AFP in London.
"I think we need more evidence that the better results are more widespread before the ripple effect spreads beyond the United States."
In Europe, London stocks dropped by 0.7 percent amid ongoing Brexit uncertainty, while Paris also sank.
However Frankfurt rose 0.6 percent, aided by soaring first-quarter revenues and profits for German software and cloud computing giant SAP.
"Although investors might have hoped that record highs in the US would prompt gains in the rest of the world, the current lack of correlation across global markets means that there is less read-across than usual," Interactive Investor analyst Rebecca O'Keeffe told AFP.
"Suggestions that leaders within China's ruling party will focus on economic reforms and will hold back on unnecessary stimulus is dampening market sentiment in Asia."
On oil markets, both main contracts ticked downwards after hitting six-month highs on the back of news that Washington would end a waiver for several countries from US sanctions on Iran.
Prices had already been surging on hopes for China-US trade talks and for an output cap by OPEC and Russia.
There has been speculation OPEC kingpin Saudi Arabia could step in to fill the void left in the market by the removal of Iranian crude, which would temper prices.
But Saudi energy minister Khalid al-Falih said Wednesday that the kingdom has no immediate plans to raise oil output.
- Key figures around 1540 GMT -
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London - FTSE 100: DOWN 0.7 percent at 7,471.75 points (close)
Frankfurt - DAX 30: UP 0.6 percent at 12,313.16 (close)
Paris - CAC 40: DOWN 0.3 percent at 5,576.06 (close)
EURO STOXX 50: FLAT at 3,502.63 (close)
Tokyo - Nikkei 225: DOWN 0.3 at 22,200.00 (close)
Hong Kong - Hang Seng: DOWN 0.5 percent at 29,805.83 (close)
Shanghai - Composite: UP 0.1 percent at 3,201.61 (close)
New York - Dow: DOWN 0.15 percent at 26,615.22
Euro/dollar: DOWN at $1.1191 from $1.1227 at 2100 GMT on Tuesday
Pound/dollar: UP at $1.2945 from $1.2938
Euro/pound: DOWN at 86.44 pence from 86.78 pence
Dollar/yen: DOWN at 111.82 yen from 111.86 yen
Oil - Brent Crude: DOWN 11 cents at $74.40 per barrel
Oil - West Texas Intermediate: DOWN 50 cents at $65.81