Can wash sales turn profit into loss after taxes?

External question — Personal Finance Stack Exchange Author: Zesty Original post: https://money.stackexchange.com/questions/126288 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Consider a person who repeatedly changes allocation between 2 securities within a few days, by selling the security whose prices went up and buying the security whose price when down. Is it possible to have profits before taxes and yet loss after taxes, due to the Wash Sale rule? Do I understand correctly that there'll be a 30% tax on the profit-making security and the loss won't be deducted on the loss-making security because of the frequent trading, and therefore a loss after tax could result, despite profit before tax? EDIT: The above is a wrong example, as pointed out below by glibdud. I will try to think of a better example. In the meantime, my question/thought is... assume that you have a small net gain from all your trades. Can that profit become a loss after tax, especially considering frequent trades in less than 30 days? Because the tax isn't on the overall gain/loss but on individual trades.