A common concern among investors is running out of money in retirement. Combating this concern, the “4% rule” is widely presented as a simple way to help your money last. Created in 1994 by financial planner William Bengen, the 4% rule says if you withdraw 4% of your nest egg each year, adjusted annually for inflation, there is a 90% chance your money will last at least 30 years. Yet despite its notoriety, the 4% rule is not without issue.