In Europe, the FTSE 100 index of leading British shares was up 0.3 percent at 7,170 while the CAC 40 in France rose 0.4 percent to 5,290. Germany's DAX was steady at 11,525. U.S. shares were set to rise modestly at the open, with Dow futures and the broader S&P 500 futures 0.3 percent higher.
Once again, the focus will be on the British Parliament where lawmakers are set to vote on whether the country should crash out of the European Union on March 29 without a deal. That proposition is set to be heavily defeated, meaning that lawmakers will have the option on Thursday to back an extension to the country's departure date. However, any delay will require the unanimous support of the other 27 EU nations and it's unclear what they would do and what they would insist upon in return for granting the extension.
The British pound has borne much of the Brexit-related moves in markets, particularly over the past few days. On Wednesday, it was up 0.7 percent at $1.3164 as traders are hoping the country avoids a "no-deal" outcome.
"For traders, a long extension would be preferable to a short one, unwinding some of the fears that have built up as we head into the 29 March deadline," said Joshua Mahony, Senior Market Analyst at IG.
Investors are also waiting for more details on any potential trade deal between the U.S. and China. Costly tariffs have hurt both nations and investors hope a deal can be struck to at least take some pressure off the global economy, which has shown signs of cooling off.
Earlier Asian markets had a more difficult session. Japan's benchmark Nikkei 225 dropped nearly 1 percent to finish at 21,290.24 while Australia's S&P/ASX 200 lost 0.2 percent to 6,161.20. South Korea's Kospi slipped 0.4 percent to 2,148.41. Hong Kong's Hang Seng fell 0.5 percent to 28,776.04, while the Shanghai Composite dipped 1.1 percent to 3,026.95.
CURRENCIES: The euro was up 0.1 percent at $1.13 while the dollar was steady at 111.38 yen. ENERGY: The price of benchmark U.S. crude oil rose 59 cents to $57.46 a barrel. It rose 8 cents to $56.87 a barrel Tuesday. Brent crude rose 56 cents to $67.23 a barrel.