Worries over surging inflation and a new variant of the coronavirus are roiling the U.S. corporate junk bond market, though some believe the tumble could draw investors seeking higher yields. Spreads, which indicate the yield premium investors demand to hold junk-rated debt over safer U.S. Treasuries, also widened the most since the beginning of the COVID-19 pandemic. Among the factors driving the moves were fears that higher inflation will force the Federal Reserve to normalize monetary policy faster than expected, as well as a rush away from comparatively risky assets on worries over the Omicron variant, analysts said.