In the 4/18/16 blog I showed a study about US tax day (normally April 15th). The reason tax day may be important is that it is the last day that people can make IRA contributions to count for the previous tax year.
This can create a last-minute rush and you will often have an inflow of funds heading into the market right around and on April 15th. Fund managers will often put this money to work immediately and it creates a positive bias for the market. Below I have updated the study and included a profit curve.
Strong stats and a good looking curve that has moved from lower left to upper right. Traders may want to keep both this and April opex in mind next week.