According to producer Frank Marshall via his Twitter account, the 4th movie in the Bourne franchise will be now looking to shoot later than expected and will be released in summer of 2011.  Originally the plan was to shoot this summer, however it seems like everything isn’t quite ready yet, though both Matt Damon and director Paul Greengrass are on board.

- Dennis

Source:
http://www.firstshowing.net/2009/04/12/frank-marshall-says-bourne-4-will-hit-in-summer-2011/