三十天之内先买后卖，应该不算wash sale。
https://www.law.cornell.edu/uscode/text/26/1091
(a)Disallowance of loss deduction
In the case of any loss claimed to have been sustained from any sale or other disposition of shares of stock or securities where it appears that, within a period beginning 30 days before the date of such sale or disposition and ending 30 days after such date, the taxpayer has acquired (by purchase or by an exchange on which the entire amount of gain or loss was recognized by law), or has entered into a contract or option so to acquire, substantially identical stock or securities, then no deduction shall be allowed under section 165
虽然法律文字上说： within a period beginning 30 days before the date of such sale .... the taxpayer has acquired ... substantially identical stock or securities, then no deduction shall be allowed
那么，如果我仅仅是5/1买了某股票，5/2全部卖掉，有loss。根据以上定义，由于5/2卖掉之前30天我买了这个股票，这个也是wash sale？道理说不通。