The pan-European Stoxx 600 index opened 0.1% lower as markets were uncertain ahead of the latest inflation reading. June’s consumer price index is expected to show overall U.S. inflation, including food and energy, rising above May’s 8.6% level to 8.8%, according to Dow Jones estimates. The tepid reading expected on Wednesday could prompt the Federal Reserve to raise interest rates by another 75 basis points at this month’s meeting. Last month, the Fed raised its benchmark interest rates by three-quarters of a percentage point to a range of 1.5%-1.75% in its most aggressive hike since 1994.

US stock futures were little changed overnight on Tuesday as investors awaited inflation data. In Asia-Pacific markets overnight, stocks were higher as China released trade data and the Bank of Korea and the Reserve Bank of New Zealand raised interest rates. Other data released earlier on Wednesday showed the UK economy grew unexpectedly in May with output rising 0.5%, according to the Office for National Statistics. A Reuters poll of economists had expected zero growth in May from April. — CNBC’s Yun Li contributed to this market report.