Quote from hajimow:
You are right but not 100%. Cash account has its own annoying rule. Let's say you have 10K and buy 10K of stock X and sell it at 11000 and then one hour later you buy 10K of the same stock and sell after one hour. This way, you have violated trade settling rule. The first trade was fine but the cash from the first trade will settle after 3 business days but the broker lends you money for the second trade and before paying the broker's money you cannot sell the shares !!!. You have to wait for 3 days so your money from first trade becomes available and pay broker's money and then sell your shares !!. Much worse than pattern daytrader rule.
