Near 10:05 a.m. ET, the Dow was up 63 points (0.36%), the S&P 500 was up 7 points (0.38%) and the Nasdaq was up 16 points (0.35%).
Stocks closed lower but mostly little changed during the last four trading sessions, amid anxiety over the British referendum next week. European indexes, which also fell, were higher in trading on Wednesday.
Treasury yields were little changed, as the flight to safety we saw over the last few days slowed down. The 10-year yield was down by less than one basis point to 1.611%.
Germany's 10-year Bund yield, which went negative for the first time ever on Tuesday, was unchanged at -0.004%.
Meanwhile, West Texas Intermediate crude oil futures were down 1.2% to $47.91 per barrel; on Tuesday, the American Petroleum Institute reported an unexpected build in inventories.
At 2 p.m. ET, the Federal Reserve is expected to announce that it is leaving interest rates unchanged; traders are pricing in a 0% chance of a hike today, according to Bloomberg's World Interest Rate Probability function.
The statement will be accompanied by an updated summary of economic projections and a new dot plot that charts where FOMC members think interest rates should be over the next few years. Yellen will hold a press conference shortly after.
In other economic news:
- Producer prices rose more than expected in May, mostly due to a rise in gas costs. The producer price index (PPI) for final demand rose 0.4%.
- Industrial production slipped yet again last month, by 0.4%, as durable-goods production slowed. Mining production rose for the first time in nine months, thanks to coal.
- And, manufacturing in New York unexpectedly spiked in June. The Empire State general business conditions index rose to 6.01 and had been forecast at -4.90.