As epo39b says, the online Deluxe version can't handle security sales, so I'm assuming you're referring to the desktop versions, both of which do support the reporting of security sales.
As I recall, the main benefit of Premier over Deluxe is that Premier has specific "guided" interview for the sale of stock acquired via the various employee stock incentive programs like RSUs, NQSOs, ISOs, ESPPs, etc. Sales of these securities present some challenges since the broker most likely won't report the correct basis to use for the sale on the 1099-B itself, (although they are required to assist you to get to the correct basis and typically do so by sending some "Supplemental Information" along with the 1099-B, assuming the sale is "covered"), and the exercise or sale of the stock can create "compensation" income that needs to be reported, and added to the "out of pocket" cost basis.
So if you are selling any stock acquired via an employee stock incentive program it might be worth your while to upgrade to Premier.
Tom Young
