I rolled over a 401(k) from an employer when I changed companies 14 years ago. I only now started wondering whether I will need to know the original sources of the contributions to that rollover account. I asked the company that manages the 401(k) and they said that they did not have that information (they merely list the entire amount as "rollover" on their statements). I called my previous employer and they said that they did not have the information, and that they were unsure what company managed the funds at that time, but believe it was a company that went under. They suggested that since it was rolled over the firm may have sent me a 1099 the year I rolled it over [which I am sure did not happen], or perhaps filed one with the IRS. I've been on the line with the IRS to see if they can tell me, but I'm still waiting. Isn't this information that I will need when I finally want to tap into this "rollover" portion to be able to determine my cost in it, and if it is information I will need, does anyone have a clue on how I can find it out?

GrayMa: for most participants in 401(k) plans all of their contributions are pre-tax, and hence all withdrawals are fully taxable. It doesn't matter whether the funds at the time of the rollover to the new 401(k) were due to your contributions, or the company's, or earnings in the account. The exception is if you think that some of the contributions you made to your old company's 401(k) were with after-tax money, because in that case when you start taking withdrawals some will be tax-free to you. So - do you think you made some after-tax contributions? If so, it's going to take some good detective work on your part to determine how much was after-tax versus pre-tax. I suggest starting with old account statements that you should have received from the plan admonistrator at the time you were invested in that old 401(k) - the quarterly or annual summaries should state whether the source of your contributions were pre-tax or after-tax. If you kept your old pay statements that would be another way to figure it out.