Which Anthropic Shares Should You Sell First?

By Joe Forish, CFA, CFP®|Published On: Oct 14, 2026|Categories: Financial Planning, ISOs, NSOs, RSUs|

The moment Anthropic’s lockup expires in May 2027, you’ll face a decision that’s easy to overlook in the rush to sell: which Anthropic shares to sell first. Not which ticker. Not how many. Which specific lots — acquired at which prices, on which dates, under which grant type.

That decision is called tax lot selection, and at Anthropic’s expected valuations, getting it wrong could cost you six figures in taxes you didn’t have to pay.

This article explains how to minimize taxes when selling Anthropic shares by starting with which lots to sell first.

The Default Will Hurt You

Most invesstment accounts default to FIFO, first in, first out. When you place a sell order, the oldest shares you own are treated as sold first.

For Anthropic employees who’ve accumulated shares across years of RSU vesting, ISO exercises, and NSO exercises, at dramatically different prices, FIFO is almost certainly the wrong method.

Here’s why. Your oldest shares are your lowest-basis shares. They carry the largest embedded gains. Selling them first means paying taxes on the most gain possible.

Specific identification flips this. You choose which lots to sell. That means you can sell your highest-basis lots first. They have the smallest gain, and the smallest tax bill. Then, you hold your lowest-basis lots until you’re in a better position to absorb the gain. Getting the Anthropic shares sell order right is the difference between an optimized exit and a default one.

Electing Specific Identification: Do This Before Lockup Expires

To use specific identification, you must affirmatively elect it before you sell. You cannot go back and reapply it after the fact.

Some brokerages handle this online; others require a phone call. The mechanics vary by custodian. What doesn’t vary: this is a setup step, not a selling step. Have this conversation before the lockup expires, not while you’re placing orders in a live market.

If you are required to speak to your brokerage, here are the steps:

Contact your broker before the first sell order to elect specific ID
Designate the specific lots by acquisition date and price at the time of sale
Get written confirmation that the selection was accepted

There are a lot of moving pieces, but the payoff could be significant, potentially saving you hundreds of thousands of dollars in taxes.

Understanding Your Lots: ISO, RSU, and NSO Basis Side by Side

Before you can identify your highest-basis lots, you need to understand how basis is established across each grant type. Anthropic RSU vs. ISO taxes work very differently and so does the basis calculation for each.

RSUs

RSUs are the simplest case. When an RSU vests, you recognize ordinary income equal to the fair market value of the shares on the vest date. That FMV becomes your cost basis.

If you received RSUs that vested at $150 per share, your basis in those shares is $150. On the other hand, if you received RSUs that vested at $300 per share, your basis is $300. Deciding which RSU shares to sell first comes down to this: sell the highest-basis lots first. The taxable gain relative to the sale price is smaller.

The long-term vs. short-term distinction still applies: shares held more than one year from the vest date are taxed at long-term capital gains rates. Shares held less than one year are short-term, taxed as ordinary income.

NSOs

NSOs are taxed at exercise. When you exercise a nonqualified stock option, the spread (the difference between the exercise price and the fair market value on the exercise date) is recognized as ordinary income. Your cost basis becomes the exercise price. Ask for a 1099 Supplemental Information Form so you capture the correct cost basis.

For example, you exercise an NSO with a $10 exercise price when shares are worth $200. You recognize $190 as ordinary income. Your basis in those shares is $200. Any gain above $200 when you eventually sell is a capital gain.

If you exercised NSOs at different times when the share price was at different levels, you’ll have lots with different bases. Find the lots exercised closest to the current price (your highest-basis lots) and prioritize those when you’re deciding what to sell.

ISOs

Deciding which ISO shares to sell first is the most complex part of the sequencing decision, and it requires care.

If you meet the holding period requirements (two years from the grant date and one year from the exercise date) the gain from an ISO sale is taxed at long-term capital gains rates, not ordinary income rates. That difference is meaningful.

The complication is that ISO exercises can trigger the alternative minimum tax. The spread at exercise, even if you don’t sell the shares, is an AMT preference item. If you exercised ISOs in 2025 or 2026 ahead of the IPO, you may have already incurred an AMT liability for those tax years. If so, you have an AMT credit carryforward captured on Form 8801 that can be used to offset future regular tax liability.

This creates a sequencing nuance. Selling high-basis ISO shares with small gains reduces your regular tax, which can slow AMT credit utilization. Your advisor needs to model this explicitly rather than applying a one-size-fits-all rule.

One more ISO consideration: a disqualifying disposition occurs if you sell ISO shares before meeting the holding period requirements. A disqualifying disposition converts the gain to ordinary income, eliminating the long-term capital gains benefit. Whether to preserve qualifying ISO status or accept a disqualifying disposition depends on your marginal rates, the size of the gain, and your AMT credit position. There is no universal answer. You must run the numbers in your specific situation.

Which Anthropic Shares to Sell First: The Sequencing Framework

With that foundation, here is how to think about the sell order.

Start with Your Highest-Basis Lots

Across RSUs, ISOs, and NSOs, identify the lots where the gap between your basis and the expected sale price is smallest. Those lots generate the least taxable gain per share sold.

Prioritize Long-Term Lots

A high-basis lot held more than one year beats a high-basis lot held less than one year, because long-term capital gains rates are meaningfully lower than ordinary income rates. For many Anthropic employees, that’s the difference between a 20% federal rate and a 37% federal rate on the same dollar of gain.

Protect Qualifying ISO Dispositions Where Practical

When you’re inside the holding period window on some ISO lots (less than two years from grant date or less than one year from exercise date) consider whether you want to sell those shares in the first round at all. Selling them triggers a disqualifying disposition and ordinary income treatment. If you have other lots available, use those first and let the ISO lots mature to a qualifying disposition.

Model AMT Credit Utilization before Finalizing the Sequence

If you’re sitting on a large AMT credit carryforward from prior ISO exercises, your CPA and financial advisor should model how different selling sequences affect how quickly that credit gets absorbed. Sometimes selling lower-basis lots, which generates more regular tax, accelerates AMT credit utilization in a way that’s net favorable over a multi-year horizon. Don’t make this assumption without the math.

Account for California’s Flat Treatment of Capital Gains

California taxes capital gains as ordinary income. There is no preferential long-term capital gains rate at the state level. This doesn’t change the federal analysis, but it narrows the spread between holding and selling at the state level, especially relevant when evaluating whether to trigger a disqualifying disposition on ISO shares. The federal benefit of qualifying ISO treatment is partially offset by the California impact.

A Concrete Example: Which Anthropic Shares to Sell First

Suppose lockup expires and Anthropic shares are trading at $400. You need to sell 500 shares and you’re choosing among three lots:

Lot	Type	Basis	Shares	Gain / share	Holding Status
A	RSU (vested Jan 2025)	$150	500	$250	Long-term
B	RSU (vested Nov 2026)	$320	500	$80	Short-term
C	ISO (exercised Dec 2024)	$200	500	$200	Long-term (if held to May 2027)

A Lot federal tax (long-term): $250 × 500 = $125,000 gain at 20% = $25,000

B Lot federal tax (short-term): $80 × 500 = $40,000 gain at 37% = $14,800

C Lot federal tax (long-term ISO): $200 × 500 = $100,000 gain at 20% = $20,000

If you can only sell one lot, Lot B generates the least federal tax, despite being short-term. It’s because the gain per share is small enough that the higher rate doesn’t overcome the smaller base. Lot A is the most expensive to sell.

This is a simplified illustration. Your actual situation will include state taxes, the 3.8% net investment income tax, your AMT credit position, and other income in the year of sale, so it may change the answer. The point is that the math is not obvious, and FIFO won’t do it for you.

What to Do Before Lockup Expires

Selling Anthropic stock after lockup requires a plan built before the lockup expires, not after. Anthropic lockup tax planning is most effective when you have months to model the sequencing, not hours. You don’t have to wait until May 2027 to do this work. The most valuable thing you can do right now is build your share inventory.

Pull up your Anthropic equity records and document every lot: grant type, grant date, exercise or vest date, price at vest or exercise, number of shares, and whether the lot meets long-term holding requirements by May 2027. You’re building a map of what you have and what each lot costs to sell.

Then contact your brokerage and confirm that specific identification is available and elected for your account. Ask how they handle lot designation. Some require advance designation in writing; others allow same-day designation at the time of sale.

Bring your lot map to your CPA and financial advisor before lockup expires. The multi-year sequencing analysis. ISO holding periods, AMT credit utilization, and stock concentration management takes time to model. Knowing which Anthropic shares sell first in your specific situation requires that analysis. You want a plan in place before you’re placing sell orders, not after.

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