In January, when Mitt Romney released his 2010 tax returns to the public, he did not release the "Report of Foreign Bank and Financial Accounts” form, which taxpayers who own Swiss bank accounts, like Mitt Romney, are required to file. Had Mitt Romney released that form, on page 2, under line 15 ("Maximum value of account during year reported”), the public would have learned how much money Mitt Romney held in his Swiss bank account.
H/t Huffington Post.