Of course the tax sensitive method is legit. Personally, I have the disposal method set to "LIFO" for all of my accounts, with the exception of the one brokerage account that I utilize specifically for day trading - that is set to "Intraday First In, First Out." For any trade I make (other than multiple trades on a single ticker during the same day) I ALWAYS choose the specific tax lot of shares that I put up for sale...