Day Trading Taxes: Wash Sales, Trader Status, and Section 475

The rule: if you sell a security at a loss and buy the same or a substantially identical security within 30 days before or after that sale, the loss is disallowed for that tax year. It is not deleted — it is added to the cost basis of the replacement position and the holding period is adjusted.

Two details do the damage. First, the window is 61 days wide, not 30: thirty days before the sale, the sale day, thirty days after. Second, it applies across accounts, including an IRA in some circumstances, which is the version that genuinely destroys a loss rather than deferring it.

For scalpers and momentum traders the practical effect is that within-year losses churn continuously into basis, and the number that matters is whether you are flat and stay flat through the year-end window. A trader who is flat by mid-December and does not re-enter until February generally sees the deferred losses resolve. A trader who is holding the same names into January can carry a phantom gain into the return.

There is no checkbox for this. Trader tax status is a facts-and-circumstances determination based on whether your trading is substantial, regular, frequent, and continuous, and whether you are seeking profit from short-term price movement rather than from dividends, interest, or appreciation.

In practice the factors that matter are trade count, average holding period, hours devoted, whether the activity looks like a business, and consistency across the whole year rather than two hot months. Nobody outside the IRS can promise you a specific threshold, and any source that quotes an exact trade count as a guarantee is overstating it.

What status buys you: trading expenses — data, platforms, education, home office, margin interest — become business expenses rather than the essentially unusable miscellaneous itemized deductions. It also opens the door to the Section 475 election, which is the part that actually changes the arithmetic.

A trader who qualifies can elect mark-to-market accounting. Open positions are treated as sold at year-end fair value, gains and losses become ordinary rather than capital, and — the important part — wash-sale rules no longer apply to those positions. So does the $3,000 annual capital-loss limitation: a bad year becomes a fully deductible ordinary loss rather than a loss you drip out over the next decade.

The trade-off is symmetrical. You give up long-term capital gains treatment on anything held in the trading account, and the election is not casual — it has a filing deadline that sits at the beginning of the tax year it applies to, not at the end, and revoking it is its own procedure.

This is the single highest-leverage decision in an active trader's tax life, and it is time-sensitive in a way most people discover a year too late. If you traded heavily last year and are still in the game, this is the conversation to have with a CPA who works with traders specifically — not in April, but early.

Your broker reports what it is required to report. It is not building you a tax strategy, and its wash-sale calculation is per-account, so a trader running two or three brokers has to reconcile across them — brokers do not do that for each other.

Keep the raw trade-by-trade export from every platform for every year, not just the summary. If a number ever gets questioned, the execution log is the evidence and a screenshot of a P&L page is not.

The failures I have watched cost people real money, in order of frequency: assuming the 1099 net number is the answer; ignoring wash sales until filing season; missing the 475 election window; not reporting foreign brokerage accounts where reporting was required; and trading through an entity someone set up from a forum post without understanding what it obligated them to file.