I've been reading the SEC document regarding Reg T + 3 settlement rules: http://www.sec.gov/investor/alerts/cashaccounts.pdf and was wanting to clarify the timing of T+3. Specifically, I'm trying to clarify if T+3 means "after the end of day T+3". Example: So if I sell security A and buy security B with those proceeds on Monday, then T = Monday T+1 = Tuesday T+2 = Wednesday T+3 = Thursday T+4 = Friday If I sell security B on Tuesday, Wednesday or Thursday I'm thinking that would be a violation of Reg T (freeriding), but I'm not sure specifically about Thursday. Specifically, when it says my funds from selling security A will settle "on Thursday" does that in practice actually mean that my funds settle "after the end of the day Thursday and they won't be available for use until Friday (T+4)?" I can't find a specific example of selling on T+3 (all the examples seem to address T+4), and indicate that selling Friday (T+4) is OK, but leads me to believe that selling on Thursday (T+3) is freeriding and must be avoided. But I'd like to confirm the understanding if others can oblige. I can't find a specific T+3 sale date addressed in any examples. The example on the SEC site says can't be sold "prior to Thursday" which leaves things vague imho. Here's from the SEC document; "The settlement date on the sale of the ABC stock that the investor used to pay for the purchase of the XYZ stock would be Thursday (three business days after the date of the sale). Since the investor used the proceedsfrom a sale of securities that has not settled yet, to purchase the XYZ stock, the investor cannot not sell the XYZ stock prior to Thursday without adding additional cash to the account to cover the purchase price of the XYZstock." I appreciate any clarification. Does "cannot sell ... prior to Thursday" actually mean "cannot sell until Friday?" Or would selling on Thursday be OK? fwiw I'm trading in IRA at IB.