It could be a boring two days.

New Fed Chairman Jerome Powell is presenting his first semi-annual monetary policy report to Congress starting on Tuesday. If history is any guide, he will try hard not to commit any news in his two days of questioning from representatives and senators.

Of course, it's unlikely Powell can do anything more alarming to the markets than what they've already gone through this month. But when Fed Chairs talk, markets tend to listen.

Over the past 10 years, under both Janet Yellen and Ben Bernanke, the policy reports presented to Congress have not moved the markets too much. Under Yellen -- from 2014-2017 -- the S&P 500 averaged a gain of 0.36% over the two days of testimony. Under Bernanke -- from 2008 through 2013 -- the index averaged a gain of 0.65% over the two days.

There is, however, a bit of a tendency to go one way on the first day of testimony, and the other way on the second. The S&P 500 has reversed direction from the first day to the second 13 out of 20 times over the past 10 years, based on an informal analysis of FactSet data.

The largest two-day decline in the S&P 500 during the monetary policy report was 1.41% over March 1-2 in 2011. The biggest two-day gain was 2.9% over Feb. 24-25 in 2009.