I don't know why. I guess brokage company was acquired a few times. I mailed the initial purchase record and IRS oked my reply.
Starting 2011, all accounts transfer shall include the transaction history. It is tedious to follow all the buy/sales if you buy/sell the same stock(s) in different batches. With stock split and transction over the years, it is quite some work. A lot of brokerage firm offers electronic download. that makes things easier.
