Chip stocks came under pressure, with ASM International ASMI.AS, ASML ASML.AS and Infineon Technologies IFXGn.DE down more than 2% on concerns about a global semiconductor shortage. By Sruthi Shankar May 19 (Reuters) - European stocks headed lower on Wednesday, tracking weakness on Wall Street, as investors grew wary of rising inflationary pressures increasing the odds of an early tightening of monetary policy. "But Europe has lot less risks because we haven't performed as well, and from the quantitative easing point of view, the ECB has been clear that they will continue for some period of time."