For example, if I close a brokerage account and move the monies to an account with a separate company, is there a reason to keep records beyond the tax year, or beyond the time to retain tax documents?
I recently closed a brokerage account and the brokerage company charged me a fee for closing the account because they have to keep records for 7 years. Forbes states to
keep brokerage statements indefinitely for taxable accounts. You are responsible for reporting the cost basis of any security you sell to calculate the capital gains tax.
So in today's world with being able to have electronic copies of everything, it shouldn't be hard to keep a copy somewhere.