Through Alan Greenspan's reign, across the Ben Bernanke years and now during the Janet Yellen era, Fed minutes have been market movers, but more positive under the current Fed chair.
Going back to early 2001, the Fed minutes were released 114 times and the S&P 500 was higher nearly half the time with an average gain of 0.8 percent, according to data provided by Kensho, a quantitative tool used by Wall Street trading firms.
But during the much shorter tenure of Yellen, the market has been higher two-thirds of the time on the days when minutes are released, also for an average gain of 0.8 percent. Fed minutes release days, under Yellen, have also been good days for energy and consumer discretionary stocks. Minutes from the December meeting will be released at 2 p.m. ET Wednesday.