I have a situation I have consulted with few tax advisors who were unable to either provide a solution or to recommend a tax expert who can help me resolve the issue.
The issue is related to a non USA retirement plan I started and funded while I was not a USA person nor working in the USA. This took place from 1979 to 1998. In 1998 I moved to the USA, stopped contributing to the foreign retirement account and started contributing to a 401K. From 1998 to 220 the foreign retirement account was frozen, not receiving contributions or sending distributions, it was growing according to the investments in the stock market. In 2020, I took full distribution of that foreign account. My understanding is that I will have to pay tax on the capital gain from 1998, when I became a US person, until 2020, when received the full distribution. The problem I have encountered is that the organization responsible for providing the value of the account at the time I became a US resident in 1998 no longer has anything to do with that account. They passed all the records to another Company. The new company claims they do not have historical records, all they have are records as of the day they took over the account in 2010.
How do I report the capital gain if I do not have the supporting document that enable me to calculate the cost basis?
