Updated July 28, 2026. Quick answer: Sell across multiple tax years rather than in one block, identify the specific lots you are selling rather than defaulting to first-in-first-out, and pair realised gains with harvested losses where you have them.
Three levers, in order of size
- Spread across tax years. A single large sale can push the gain into higher rates and trigger income-based surcharges. Splitting it is usually the largest single saving available and requires no cleverness.
- Choose your lots. Specific identification lets you sell the highest-basis shares first and realise less gain per share sold. The default method rarely does this for you, and the election has to be made at the time of sale.
- Pair with losses. Realised losses elsewhere offset these gains directly. This is when a loss you have been carrying is genuinely worth something.
Write the rule before you start
The reason concentrated positions persist is that every sale feels like a market call. A predetermined schedule — a fixed number of shares each quarter, or a target percentage of net worth — removes the decision from the moment when it is hardest to make.
If you also hold options or RSUs in the same company, count them in the exposure. People measure concentration by shares held and forget the unvested pipeline pointing at the same ticker.
Sources
IRC §1012; Treas. Reg. §1.1012-1(c) (specific identification); IRC §1211(b); IRC §1222.
This states what the cited authority says. It is not tax advice.