I'm trying to understand how the T+2 rules apply when trading only one symbol in a cash account. Let's say I bought QLD (2x QQQ Bull ETF) a month ago and my entire account consists of this position. On Monday's open I sell it. On Tuesday's open I use the entire account to again buy shares of QLD (using the unsettled funds), on Wednesday's open I sell this second position. Would this violate any T+2 rules? The second sale occured on the same day that the first sale should have settled, therefore, I think it's in the clear but wanted to make sure. What time of day does actual settlement occur? Is it before the open or does the time vary?