10b5-1 Plan: Cost and Tax Timing of Stock Sales

The SEC’s 2022 amendments to Rule 10b5-1 imposed a cooling-off period of up to 120 days between the day a director or officer adopts a trading plan and the day the first share can sell. The Commission adopted the changes on December 14, 2022, and they took effect February 27, 2023. That delay is the entire point of the rule — and it is also the part most equity holders price incorrectly. A plan does not change what you owe. It changes when you are allowed to sell, which is a different and frequently more expensive constraint.

A 10b5-1 plan is an affirmative defense against insider-trading liability, not a tax structure. The IRS treats a share sold under a pre-arranged plan identically to a share sold on a whim: the tax event is the vest or the exercise, and the sale only determines capital gain or loss against an already-fixed cost basis. What the plan does is remove your discretion over timing — and timing, for someone holding restricted stock units (RSUs) or stock options, is where most of the controllable money sits.

What the plan actually costs and what it doesn’t

Start with the number that gets misattributed. The cooling-off period for Section 16 directors and officers is the later of 90 days after plan adoption or two business days after the next quarterly filing, capped at 120 days. For everyone else who is not the issuer — rank-and-file employees with material nonpublic information — the cooling-off period is 30 days. Those are calendar constraints, not fees. The plan itself carries brokerage administration costs, typically a per-trade commission plus a setup or annual fee depending on the administrator, but those are rounding errors against the tax on the underlying equity.

Here is the summary block a $150k+ holder needs before modeling anything else.

Sources: SEC Fact Sheet 33-11138 (Dec. 2022); IRS Rev. Proc. 2024-40 (2025 brackets); California FTB / Behavioral Health Services Tax. Single and MFJ thresholds as noted.

Why the tax event is the vest, not the sale

An RSU is taxed as ordinary income at vest. The fair market value at the vest date multiplied by shares vested equals the income reported on your W-2, and that figure is locked the moment the shares deliver — whether you sell that day, hold for a decade, or route the sale through a 10b5-1 plan three months later. The plan touches none of it. What the plan can touch is the capital gains clock that starts at vest, because the cost basis is the vest-date FMV and any subsequent movement is a capital gain or loss measured from there.

This is where the cooling-off delay quietly imposes a cost that has nothing to do with the tax code. Suppose 1,000 RSUs vest at $85. You owe ordinary income tax on $85,000 regardless. If you wanted to sell immediately to cover the tax and diversify, but you adopted a 10b5-1 plan and the first scheduled trade is 100 days out, you carry concentrated single-stock exposure across that window. The stock can move 30% either direction before you are permitted to act. The methodology behind the vest-and-sell versus hold decision applies identically here — except the plan has removed your ability to choose.

Options behave differently and the distinction matters for plan design. Non-qualified stock options (NSOs) generate ordinary income on the spread between exercise price and FMV at exercise, with FICA applying to the employee’s NSO income. Incentive stock options (ISOs) generate no regular tax at exercise but the spread is an AMT preference item, and the favorable long-term capital gains treatment requires meeting the holding period — two years from grant and one year from exercise. A 10b5-1 plan that schedules an ISO sale inside that window forces a disqualifying disposition, converting the gain to ordinary income. That is not a tax the plan creates; it is a tax the plan’s rigid schedule can trigger if the dates are set carelessly.

The Finluxy Equity After-Tax Yield on a plan sale

The relevant question is not “what does the plan cost” but “what fraction of the equity’s pre-tax value survives the tax event the plan routes around.” The Finluxy Equity After-Tax Yield measures exactly that: net after-tax proceeds as a percentage of pre-tax FMV at the event date. For a same-day RSU sale executed under a 10b5-1 plan, the yield is identical to a discretionary same-day sale, because the plan changes neither the income nor the basis.

Take the 1,000-share RSU vest at $85 — $85,000 of ordinary income — for a top-bracket California holder.

Sources: IRS Rev. Proc. 2024-40 (top federal rate 37%); California FTB top rate 13.3%; IRS Topic 560 (base Medicare 1.45%, uncapped). Illustrative; assumes holder above all top-rate thresholds. Excludes 0.9% Additional Medicare Tax on wages over $200,000, which would lower yield further.

The yield is 48.3% — slightly under half. That figure is the honest answer to what an equity event nets a top-bracket California employee, and the 10b5-1 plan does not move it by a single percentage point on a same-day sale. The plan’s cost shows up only when its schedule forces a sale at a different date than you would have chosen, exposing you to price movement or, for ISOs, to a holding-period miss. Anyone modeling net RSU yield after federal, state, and FICA at lower income levels or in a no-tax state will see a higher yield, but the structural point holds: the plan is timing insurance, not a tax shield.

For a holder also subject to the 0.9% Additional Medicare Tax — which applies to wages above $200,000 single or $250,000 married filing jointly — the yield drops further. On the same $85,000, that surcharge adds $765 if the holder is already over the threshold from base salary, pushing net proceeds to roughly $40,247 and yield to about 47.3%. The exact figure depends on where the vest income stacks against the threshold, which is why the calculation belongs to the California RSU tax breakdown rather than a single national number.

Where the 10b5-1 plan creates genuine value

The plan earns its keep in two scenarios, and neither is a tax benefit. First, it provides the affirmative defense itself — a director or officer who would otherwise be locked out of selling for most of the year by blackout windows can establish a schedule and sell during periods they could not trade discretionarily. For someone whose net worth is concentrated in a single stock, the ability to diversify at all is the value. Second, it removes the behavioral failure mode of holding too long. An executive watching a stock climb rarely sells voluntarily; a plan that sells 5,000 shares on the first trading day of each quarter executes the diversification the executive would otherwise rationalize away.

Scenario: an officer holds 40,000 vested shares of a $120 stock — $4.8 million concentrated in one position. Discretionary selling is blocked during most quarters by blackout windows tied to earnings. A 10b5-1 plan scheduling 5,000 shares per quarter at market lets them reduce the position by half over two years regardless of blackout timing. The ordinary income was already taxed at vest; these sales generate only capital gain or loss against the vest-date basis. If the shares appreciated since vest and the holding period is met, that gain is taxed at the 20% long-term rate plus the 3.8% Net Investment Income Tax — a combined 23.8% federal — rather than the 37% ordinary rate. The plan did not create that preferential treatment, but it operationalized the discipline required to capture it.

The overlooked insight: the cooling-off period is an unhedged exposure window

Most coverage of 10b5-1 plans frames the cooling-off period as a compliance formality — a box to check before trading starts. The data reframes it as a forced holding period with no offsetting compensation. Between plan adoption and first trade, a director or officer cannot sell for up to 120 days. On a $4.8 million concentrated position, the historical one-month volatility of a single technology stock routinely runs 10–15%; across a 120-day window, a two-standard-deviation move can exceed 40% in either direction. The plan grants legal protection but imposes market risk that no one prices because it does not appear on any tax form or invoice.

Put concretely: the after-tax yield table shows the tax cost is fixed and unavoidable at 48.3%. The cooling-off exposure is the opposite — invisible, variable, and entirely a function of the calendar dates you happened to pick. A holder who adopts a plan the week before a major product announcement and a holder who adopts it during a quiet stretch face identical paperwork and wildly different real risk. That asymmetry is the actual cost of the rule, and it is absent from nearly every explainer because it cannot be reduced to a single percentage.

Practical context for the $150k+ household

For a household in this income band, the 10b5-1 decision is rarely about the dollars of administration fee and almost always about two thresholds. The first is concentration: once a single employer’s stock exceeds roughly a third of liquid net worth, the diversification value of a scheduled-sale plan outweighs the loss of timing discretion, because the alternative — holding through blackout windows and hoping to catch open trading periods — systematically delays diversification. The second is the holding-period interaction. A household with significant ISO holdings must design the plan schedule around the two-year-from-grant, one-year-from-exercise requirement, because a plan that mechanically sells into a disqualifying disposition converts a 23.8% combined long-term rate into a 37%-plus ordinary rate — a swing of more than 13 points on the entire gain. The framework for that decision overlaps directly with the ISO versus NSO tax comparison and, for holders facing the AMT trap, the AMT risk analysis for incentive stock options.

The trade-off worth weighing is discretion against discipline. A plan removes your ability to react to news — which is precisely its legal purpose and precisely its behavioral benefit. If you are confident you would sell on schedule without it, the plan adds cost and constraint for an affirmative defense you may not need as a non-insider. If you know you would hold too long, the plan buys you out of your own worst instinct. For employees navigating equity at a liquidity event, the same logic threads through the IPO equity award tax cost and the broader equity compensation tax guide for high earners. The plan is a tool for the second household, not the first.