People who open an RDSP after 2008 or those who have not maximized the government contributions may be eligible for retroactivity on the grants and bonds. However, you may not be able to collect all the retroactivity in one year. The maximum amount of grant money the government will provide in one year is $10,500. People need to be careful they are not contributing too much in one year in the hopes of attracting all the retroactivity. Confusing, I know. The calculation to figure out what to contribute in one year to get the retroactivity is not straightforward.