Not trying to be "that guy" but whats the big deal? They don't want you locking in losses for that year that you deduct and then the issue gains back the losses the next year and you make money on the stock. So if you sell and rebuy the same issue the cost basis just changes so you can't incrementally sell/rebuy a stock during short downturns and get the gains and deduct the "losses" both.
Whats complex about that?
Well Khane it's not always that clear. You can't buy the same investment 30 days BEFORE and after the loss without the rule coming into play, and for people who day trade we are talking thousands of transactions. The rule was never put into place thinking about how it affects day trading, it was to stop investors dumping losers for the write off at YE then instantly buying it back. The poop of it is in the record keeping. I understand the rule perfectly but have you seen how wash sales are listed on a 1099? The vast majority of people maybe even yourself don't really understand it. The wash disallowed but the cost basis is added to the other transaction so you don't really loose it, but it continues to roll to each new transaction in that security for the whole year unless you don't trade that security for 30 days.
So last year in just SPY alone I have $50,000+ in disallowed loss but because I don't trade in December the loss is added to final transaction, but if a person didn't understand the rule and traded even one time in that security at YE the IRS would be saying please pay tax on all gains and the loss moves to the next tax year. THis can result in massive tax bills to the the unaware.
Did you know:
This includes trading "substantially similar" asset;
This includes trading options
This includes trading in a separate account or spousal account. In fact if you trade say S&P 500 for a year and racking up numerous wash sales, then your wife buys the market in her IRA in December you have no forever given up the loss sales.
You buy stock A at $90 then it drops and you buy some more at $80, it recovers to $85 and decide to sell, do you have a taxable gain?