The Day Your Net Worth Stops Being Diversified
Somewhere in your calendar there’s a date you haven’t marked yet: the day your company’s IPO lockup expires. Before that date, you own shares on paper and can’t touch them. After it, a chunk of your net worth, sometimes most of it, becomes tradeable, taxable, and exposed to whatever the market decided your stock is worth that week. The plan you make before that date is the one that survives contact with the price chart. The plan you make on the day itself is usually panic wearing a spreadsheet.
This isn’t the “should I hold RSUs” argument. We already made that case: sell at vest, diversify, don’t let sentiment about your employer override the math. Go read that if you haven’t. This is about the specific mechanics of an IPO: the lockup clock, the tax bomb that lands the moment your shares convert to real stock, and the decisions you need to make before the countdown starts, not after.
The 180-Day Countdown
The standard IPO lockup runs about 180 days from the IPO date. Underwriters require it so early employees and insiders can’t flood the market with shares the week the stock starts trading, which would tank the price right as the company is trying to prove it deserves one.
“About 180 days” is doing a lot of work in that sentence. Some lockups have early-release provisions: if the stock trades above a set multiple of the IPO price for a stretch of consecutive days, part of the lockup can lift early. Some release in tranches instead of all at once, some tie release timing to the company’s next earnings report so insiders aren’t selling right before results come out, and some banks have discretion to waive the lockup early for select holders (rarely you, usually the founders and big institutional investors). None of this is standardized. Your specific lockup terms are in the S-1 and in your own equity documents, not in a blog post. Read them. The exact date matters enough that “sometime around 180 days” isn’t good enough to plan around.
Mark the actual date. Then work backward from it.
Double-Trigger Vesting: Why the Whole Grant Shows Up at Once
If you joined a company before it went public, your RSUs almost certainly use double-trigger vesting. This is a different mechanism from the double-trigger acceleration clause in an acquisition (that’s about what happens to unvested shares if the company gets bought and you get let go). Double-trigger vesting is about when pre-IPO RSUs convert to real, deliverable shares in the first place.
Trigger one is the service condition: you stay employed and time passes, exactly like a normal vesting schedule. Trigger two is a liquidity event, meaning the company goes public or gets acquired. Until both triggers fire, you don’t actually own deliverable shares, even if your vesting schedule says three years’ worth of grants have “vested” on paper. The company can’t hand you tradeable stock in a private company; there’s no market for it and no easy way to price it for payroll purposes.
The moment the IPO happens, trigger two fires for every tranche that already satisfied trigger one, and that catches almost everyone off guard. If you’ve been at the company four years, that could be four years of vesting landing in your account in a single week. Not spread across quarterly vest dates like a normal RSU schedule. All at once. That’s not “a nice payday.” That’s a five or six-figure (sometimes seven-figure) taxable income event compressed into one pay period, and the IRS doesn’t care that it took you four years to earn it.
The Withholding Trap: The Part That Actually Costs You Money
This is the detail that turns “exciting IPO” into “surprise tax bill in April,” and it’s simple enough to run the numbers on.
Employers commonly withhold federal tax on RSU vests at the flat supplemental wage rate, 22%, regardless of your actual bracket. That rate is designed for a normal bonus check, not for four years of equity landing in one afternoon. If your real marginal rate is higher (and after a double-trigger vest, it almost certainly is), you’re under-withheld, and the gap isn’t found until you file next spring.
Say your double-trigger vest is worth $150,000 and your actual combined marginal rate is 37%:
- Withheld at the flat 22% rate: $33,000
- Actually owed at 37%: $55,500
- Shortfall you need to have set aside: $22,500
Now scale it up. IPO vests routinely blow past $1 million in supplemental wages for the year, and once they do, the withholding rules change: current IRS rules require the flat rate to jump to 37% (the top rate) on supplemental wages above $1 million in a calendar year, not just the 22% rate on everything. That sounds like it fixes the problem. It doesn’t, not fully. Take a $1.2 million vest:
- Withheld: 22% on the first $1,000,000 plus 37% on the remaining $200,000, totaling $294,000 (a blended rate of about 24.5%)
- Owed at a 37% federal marginal rate alone: $444,000, a $150,000 gap
- Owed once you add a state marginal rate on top, say 9.3%: $555,600, a $261,600 gap
That gap doesn’t show up on a pay stub. It shows up as an IRS bill, plus estimated-tax underpayment penalties if you don’t cover it before the relevant quarterly deadline. The fix is boring and effective: as soon as you know a double-trigger vest is coming, estimate your actual marginal rate, compare it to what’s being withheld, and set the difference aside in cash the day the shares land, not the week before taxes are due. If the gap is large, make an estimated tax payment instead of waiting for filing season.
Trading Windows, Blackouts, and Why You Can’t Just Sell Whenever
Owning vested shares and being allowed to sell them are two different things. As an employee, especially one with any visibility into financials, product plans, or anything not yet public, you’re subject to your company’s insider trading policy. That usually means open trading windows tied to earnings releases, blackout periods in between, and a preclearance requirement where you have to get approval from legal or compliance before you sell, even during an open window. Miss the window and you wait for the next one, lockup or no lockup.
This is exactly the situation where a lot of people watch the stock price drift for weeks doing nothing, because by the time the window opens again, the price moved and now it feels like the “wrong” time to sell. Which brings us to the tool that exists specifically to solve this problem.
10b5-1 Plans: Selling on Autopilot
A Rule 10b5-1 trading plan is a preset, written instruction to your broker to sell a specific number of shares (or a schedule of them) at specific times or price triggers, set up in advance. Once it’s in place and the required cooling-off period has passed (generally a minimum of 90 days for individual insiders before the first trade under an updated plan, though check your company’s specific policy and the current rule), the plan executes on autopilot, including during blackout windows. You’re not making a real-time decision to sell; you made that decision weeks or months earlier, before you had any current insider information.
That timing is the entire point. You set up a 10b5-1 plan when you don’t know anything material, precisely so the plan can execute later even if you do learn something material in between. Try to set one up right before an earnings call you know is going to be rough, and you’ve defeated the purpose, and possibly created a real legal problem. Set it up early, ideally before the lockup even expires, and it quietly handles your sell-down regardless of what window is open or closed.
Timing the Pop Is a Losing Game
Lockup expiration dates are public. Everyone watching the stock knows the date, and a predictable slug of insider selling hitting the market on a known day tends to put downward pressure on the price right around then, sometimes before, as the market anticipates the supply. Trying to guess whether your stock dips the week before, spikes after, or does nothing at all is a bet on other people’s behavior, not a strategy. Professional traders with better data and faster execution are making the same guess you are, and plenty of them are wrong.
The honest position: you don’t have an edge on the exact week of lockup expiration, and pretending otherwise is how people end up holding for “just a little longer” while the stock grinds down 40% over two quarters.
The Number That Should Actually Worry You
Forget trying to time the price. The number that matters is: what percentage of your net worth is sitting in this one stock right now? For a lot of pre-IPO employees, the honest answer after a successful listing is 60 to 90%. Your house, your 401k, your cash, all of it combined is smaller than your position in one company’s stock, a company whose fortunes are also tied to your paycheck and your career.
A reasonable target is getting any single stock position down to somewhere under 10 to 15% of net worth within a defined window, not “eventually,” a specific plan with dates. Above that, you’re not investing, you’re concentrated, and concentration is the thing that turns a great IPO story into a bad decade for the people who held too long.
The Playbook
- Sell a fixed percentage immediately once you’re clear to trade. Somewhere in the 50 to 75% range is a common starting point for people with no strong conviction otherwise. This covers the withholding gap, funds a real emergency fund, and gets meaningful diversification started on day one instead of “eventually.”
- Set up a scheduled sell-down for the rest. A 10b5-1 plan that sells a fixed dollar amount or share count on a regular cadence (monthly or quarterly) over 12 to 24 months smooths out the price risk of trying to pick one exit day, and keeps working through blackout windows.
- Give some of it away, on purpose. If the vest pushes you into an unusually large income year, donating appreciated shares directly to a donor-advised fund lets you take a charitable deduction at fair market value and skip capital gains tax on the appreciation entirely, better than selling first and donating cash. It’s also a clean way to lower a single outsized tax year without changing your actual spending.
Watch the Rest of Your Tax Return Too
A big vest year doesn’t just cost you on the RSU income itself. It can quietly wreck other decisions you’d otherwise make. A Roth conversion that made sense at your normal income can become an expensive mistake if it stacks on top of a six-figure vest and pushes a chunk of the conversion into a much higher bracket, so hold off on conversions in the same calendar year as a large vest. And if you’re anywhere near Medicare age, a single unusually high income year shows up two years later as higher Medicare Part B and Part D premiums (IRMAA surcharges), calculated off the tax return from that big year specifically. Neither of these is a reason to panic. Both are reasons to look at the whole return before you file, not just the RSU line.
What to Actually Do This Week
Find your lockup date and read the actual clause, not the version you remember from onboarding. Estimate your real marginal rate against the 22% (or 37% above $1 million) withholding you’ll actually get, and set the gap aside in cash. Talk to your equity plan administrator or a fee-only advisor about a 10b5-1 plan before the lockup lifts, not after. Then pick your sell percentage and your sell-down schedule before the first trading day, so the version of you looking at a moving stock price on day one is executing a plan, not inventing one.
