Wharton finance professor Jeremy Siegel said he thinks the Federal Reserve is underestimating the degree to which inflation will be a problem, likely forcing the central bank into a sharper pivot away from stimulus and potentially catching markets off guard. Siegel, known for upbeat forecasts, made the gloomy prediction in an interview on CNBC on Oct. 1, saying he thinks “we’re headed for some trouble ahead.” “Inflation, in general, is going to be a much bigger problem than the Fed believes,” Siegel said, adding that he believes the persistence of elevated prices is going to pressure the Fed to accelerate the process of rolling back the $120 billion or so of monthly purchases of Treasury and mortgage securities. The Fed dropped rates to near-zero last year and embarked on its massive bond buying program to help the economy bounce back from the pandemic recession, a process that has also lifted …