** European chip stocks rise in a weaker market, resuming their rally even as signs of volatility emerge after a strong run this year that has raised valuation concerns for a sector seen as a key beneficiary of the AI capex boom

** Infineon IFXGn.DE, BE Semiconductor BESI.AS and STMicro STMPA.PA reverse the previous day's losses to rise roughly 2–3%, bringing their gains so far in 2026 to 108–166%

** Sector heavyweight ASML ASML.AS, Europe’s biggest company by market capitalisation, lags slightly but still gains about 1%, taking its year-to-date rise to more than 50%

** Gains in Europe come despite U.S. chipmaker Marvell Technology MRVL.O falling nearly 2% in premarket trade, even as it issues an upbeat 2029 revenue forecast

** Soitec SOIT.PA soars 20% after the semiconductor materials supplier beats quarterly estimates, extending its YTD rally to around 700% and defying expectations of profit taking

** X-Fab XFAB.PA drops 9% after surging as much as 76% in the previous session following a social media post; KBC cuts X-Fab to "reduce" saying the rally has outpaced earnings prospects

** The Philadelphia Semiconductor Index .SOX, a key U.S. benchmark for chip stocks, is up almost 80% this year, compared with a 9.9% gain in the broader S&P 500 .SPX