Recently, My son, dil, and grandkids visited us. During the course of conversation, my dil asked how to find an old 401k. Apprently her mother and oldest sister had been going through old papers and came across a 401k balance, that the oldest sister had forgotten. The company had gone through various changes, takeovers, etc. and was no longer the same company from which each had retired. This set me on the path of research (google) and I found a few suggestions. I then mentioned that RMD should take place beginning the year someone turns 70 1/2. Apparently older sister is soon to be 80. I said "uh-oh" but thought something different. Any tax deferred system, such as traditional IRAs and 401(K)s are deferred until that magical 70 1/2, unless a trust is set up etc. Even if someone has fallen behind in RMDs, there are potential methods to defray penalties. Simply forgetting, is not likely one of those methods. RMDs start out at a bit under 4% and then gravitate upwards each year. In the case of the older sister, she is very near a cumulative 40%~50% withdrawal, to catch up. There is also a 50% penalty for failure to withdraw on time and with about 10 years of failure, that would be 50% plus accrued interest penalties. IF her 401(k) were $10,000, then she should have already withdrawn about $5,000. Of that $5,000 about $2,500 of penalties + interest penalties would be deducted from the $5,000. Of course, she would still get to declare the $5,000 as income for tax purposes. That's IF her 401K was just $10,000. If it is $100,000, then she has definitely moved up a couple of tax brackets, placing more of her S.S. into taxable territory, plus a possible big increase in Medicare costs. There may be myriad ways to avoid some of that, but almost all require legal advice, imo. My dil posited that it might be better to just forget it, but no... there is still some revenue gain, just nowhere near would could have been. Plus she needs to get caught up by December 31st, or have this year included in the penalties. So don't forget 70 1/2 is also an important milestone if you have any tax deferred savings.