Literally a day ago Marvel Head honcho Kevin Feige firmly announced that their still untitled Marvel film will not be moving away from that May 6th, 2016 release date. This so happens to be the same exact day DC decided to move their mega blockbuster Batman vs Superman onto. Well now it seems things may have changed...
According to Judao Brazil it seems Warner Bros Brazil has made suggestions that Batman vs Superman will move up one week to April 28th or 29th, 2016. Of course they add that it has yet to be finalized but that the US release would also move up a week.
This could be huge or disastrous for the age ole battle between Marvel and DC. Again, take it as a rumor until an official announcement occurs.