I believe that the IRS/Government a few years back made it a requirement for all brokerages to provide cost basis, LT, ST, Gains and Losses.  This made reporting those on the 1040s much more accurately, it probably was an area where a tax payers made many mistakes on their taxes.

I remember having to manually figure out and enter all that info every year as I was preparing my taxes.  Fidelity always provided all that info, not so ETrade. It was painful.