Here is the golden goose. The wash-sale rule of IRC §1091, dissected in section “Wash Sales”, disallows a loss when you repurchase a substantially identical position within 30 days — but by its own terms it reaches only “stock or securities.” Spot cryptocurrency is neither. It is property. The 61-day window simply does not exist for it.
You can therefore sell a depressed coin at 10:00 a.m., crystallize the loss, and buy the identical coin back at 10:01 a.m. with your market exposure untouched. Let be your cost basis and the depressed sale price. The harvested loss converts immediately into a tax asset:
That loss offsets capital gains elsewhere in the portfolio, or up to $3,000 of ordinary income per year, with the remainder carried forward indefinitely (section “Tax-loss harvesting”). Unlike an equity harvest — where you must hold a merely similar fund for 31 days and eat the tracking error — the crypto harvest carries no exposure gap at all. It is the cleanest tax-loss harvest in the Code. Note the symmetry with ordinary harvesting: the repurchase resets your basis down to , so this is a deferral plus a rate-and-timing arbitrage, not free money — but a deferral with zero tracking risk is still worth a great deal.
Three caveats keep it legal and durable. First, it applies only to spot crypto held directly. A spot Bitcoin ETF is a security; its shares sit squarely inside IRC §1091, as do crypto-related equities and most futures-based products. Second, while IRC §1091 does not reach property, the IRS keeps the economic-substance doctrine in reserve; a genuine on-exchange sale and repurchase at live prices is respected, but leaving a few minutes between the legs, or using a different venue, is cheap insurance against a “no real change” argument. Third, the gap is on borrowed time — successive administrations have proposed extending wash-sale treatment to digital assets, and even crypto-friendly Senate bills now bundle a 30-day rule. Harvest while the window is open; do not build a permanent plan around its survival.