Tax-Loss Harvesting Works Like a Protective Put

A put option gives you the right to sell a security at a specific price (the “strike price”) before a specific date. If the security drops below the strike, the put becomes valuable: you can sell at the strike price even though the market price is lower.

When you own a stock and buy a put on it, that's called a protective put. It works like insurance on your position. If the stock drops, the put pays out, partially offsetting your loss. If the stock stays flat or goes up, the put expires worthless.

The catch: puts are expensive. As of August 2026, VTI (Vanguard Total Stock Market ETF) trades around $380 per share. A $375-strike protective put expiring in December 2026 (about 4 months of protection) costs roughly $10 per share. To cover $100,000 worth of VTI (about 263 shares), that's roughly $2,600 for four months of downside protection. And when the puts expire, you have to buy new ones.

What if you could get something like a protective put for nearly free?

If you hold securities in a taxable brokerage account and you keep an eye out for tax-loss harvesting opportunities, you essentially already have one.

It turns out the payout profile from tax-loss harvesting (TLH) is very similar to that of a protective put:

The “strike price” of your TLH put is your cost basis. If you bought a position at $100, your effective strike is $100. Any drop below that creates a harvestable loss.

But TLH has a critical advantage over a real put: the strike resets.

When you harvest a loss, you sell the position and buy back a similar (not substantially identical) security. Your cost basis resets to the current lower price. If the price keeps falling from there, it drops below your new cost basis and you can harvest again. Each harvest resets the strike.

This makes TLH behave like a rolling series of at-the-money puts that automatically reset their strike after each exercise.

A stock that drops from $100 to $90, then from $90 to $82, then from $82 to $76 generates three separate harvests at each new cost basis. A stock that drops straight from $100 to $76 in one move generates only one. More price movement means more harvesting opportunities.

Option “greeks” measure how a position's value responds to different market variables. Here is a concrete comparison using a $100 stock, an at-the-money 1-year put ($100 strike, ~$4.50 premium, 16% implied vol), and a 30% tax rate:

When people call TLH a “long volatility” strategy, what they really mean is that it's a long gamma strategy: you benefit from realized price movements on the downside.

Compared to a real put, TLH gives up vega (you don't profit from rising implied volatility). But it avoids theta (your “put” never decays), which is a significant advantage. A real put is a wasting asset. TLH is not.

We can quantify the relationship between volatility and TLH savings using the same Monte Carlo simulation that powers our TLH savings calculator. The model simulates investing a fixed amount per year, with tax lots entering throughout the year via dollar-cost averaging. Each lot's daily price path follows geometric Brownian motion (the same framework underlying Black-Scholes option pricing), and losses are harvested whenever a lot drops below its cost basis.

The simulation confirms what the theory predicts: tax savings scale nearly linearly with volatility. Doubling the annual volatility roughly doubles the expected annual tax savings.

For $100,000/year invested across 20 tax lots and a 30% combined tax rate:

At typical equity volatility (16%), the expected annual tax savings are roughly 6 times the annual subscription cost. At higher volatility levels (Nasdaq 100 stocks, international equities, individual tech names) the multiple climbs further.

If you wanted to get the same kind of downside protection through the options market, what would it cost?

Option 1: Buy protective puts on VTI

As of August 2026, VTI trades around $380. A $375-strike put expiring December 2026 (about 4 months of protection) costs roughly $10 per share. To cover $100,000 in VTI (about 263 shares):

Option 2: Subscribe to Harvest IY

That's roughly a 35x difference in cost. Of course the payoffs are different: a put pays the full intrinsic value in cash, while TLH pays your tax rate times the loss as a tax savings. But TLH also resets after each harvest, giving you a fresh put at a new strike. A real put expires, and if you want protection for the next year, you buy another one at full price.

If your goal is to extract value from downside volatility, TLH does it at a fraction of the cost of actual options. You get the downside gamma exposure as a side effect of a tool you'd use anyway for tax optimization.

The protective put framing captures the structure of TLH well, but the analogy has limits:

• TLH pays a fraction of the loss, not the full loss. A put pays the full intrinsic value (strike minus price). TLH pays your marginal tax rate times the loss. At a 30% tax rate, your TLH “put” has a payoff slope of 0.30, not 1.00.
• TLH is a tax deferral, not a cash payoff. When you harvest a loss, your cost basis in the replacement security is lower. This means you'll pay more tax when you eventually sell for a gain. The benefit is a time-value-of-money advantage from deferring taxes. Real value, but not the same as cash from an option.
• TLH is bounded by the wash sale rule. After harvesting, a 31-day cooldown window limits how frequently you can re-harvest the same security. A real put has no such constraint.
• TLH savings are path-dependent at the lot level. A put expires and settles at a single point in time. TLH is a continuous process that depends on the entire path of each lot's price throughout the year. The same annual volatility number can produce different TLH results depending on the specific sequence of daily moves. (This is the gamma dimension of TLH: it benefits from the zig-zag path, not just the endpoint.)
• Options are tradeable. You can sell your put if your view changes. A TLH subscription isn't a transferable financial instrument.

These differences matter. TLH isn't a replacement for buying puts. But the structural similarity, fixed cost, payoff on downside moves, resetting strike, makes the analogy useful for understanding why TLH is valuable and when it's most valuable.

If you hold volatile assets in a taxable brokerage account (individual stocks, sector ETFs, international equity funds) you're sitting on vol exposure that you're not being compensated for. Every dip is a potential tax savings that disappears when the price recovers.

Tax-loss harvesting is the mechanism that converts that volatility from a source of anxiety into a source of value. A monitoring tool like Harvest IY is what makes the mechanism practical. It watches for opportunities continuously so you don't have to.

The “premium” for this protective put is a subscription fee. At $19/month, the break-even point is just $228/year in harvestable tax savings. That's less than what $100,000/year invested across 20 tax lots generates at even 8% annualized volatility. At typical equity volatility, the expected return on that “premium” is 6x or more.

Volatility is already in your portfolio. The question is whether you're capturing the tax benefit from it.