The deal on Etrade is that you if you sell some shares that you have owned for more than 3 days, you can reinvest them right away. But they warn you that if you sell those reinvested shares before three days are up, that they will put something like a 90 day trade restriction on your account. As long as you sell, then buy and hold it for at least 3 days, you're okay. What they don't want is for you to sell, then buy, then sell again before the original sell has had a chance to clear, which takes 3 days. Or you also can't buy, then sell before 3 days are up, because the buy order takes 3 days to go through.
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