You've known for years that competition was coming. Every drug with a dominant position eventually faces it. But knowing it intellectually is a very different thing from the morning you learn that a biosimilar has just cleared FDA approval and will soon compete with your company's flagship drug.
A large share of your wealth is likely in company stock. Years of restricted stock units (RSUs) have accumulated during the period when this drug owned its category. That concentration was built during the dominance era. The era just changed.
What does biosimilar competition mean for employees holding concentrated pharma stock?
It means the stock you hold is moving from a dominance period into a multi-year transition period with a very different risk profile — and the time to decide how much of your household's future should stay exposed to that transition is while the impact is still a forecast, not a reported result.
A biosimilar doesn't break a franchise overnight, but the stock reprices anyway
The drug that drives a large share of company revenue today is unlikely to contribute anywhere near that share three years after competition enters. That pattern is well established. Market share erosion and pricing pressure following biosimilar entry are predictable and persistent. They don't happen all at once or on the announcement date, but they do arrive.
What happens is quieter. The market reprices the stock to reflect a lower forward earnings estimate — the consensus view of what the company will earn in future years. That repricing plays out both before and during the quarters in which this revenue impact becomes visible. You built wealth holding through the dominance years. You are now holding through something different, and the risk profile has changed even if the stock price hasn't moved much yet.
Your low cost basis is real, but it isn't a reason to hold forever
Years of shares vesting at lower prices gave you a low cost basis — the value you were taxed on when the shares vested, which determines your gain when you sell. Selling means recognizing that gain and paying tax on it. That cost is real, and it's worth respecting.
But here's the distinction that matters. The tax cost of reducing a concentrated position is a one-time event. The risk of holding through a multi-year erosion story is a recurring exposure that doesn't shrink because the tax bill is large. These are not the same kind of thing. Treating them as equivalent — "the tax is too high to sell" — is exactly the reasoning that maintains a concentrated position long after the conditions that built it have gone away.
The planning window is open while the impact is still a forecast
Once the revenue erosion shows up in reported quarterly earnings, two things happen at the same time. The stock has already begun repricing, so the decision to reduce the position costs you more as the share price declines. And watching the number fall in real time makes the decision harder emotionally. Price and emotion move against you together.
The employees who address concentration before the impact is fully visible aren't predicting where the stock goes next quarter. They're answering a different question — how much of the household's financial future should depend on a competitive transition they can't control. That's a planning decision about your own exposure, not a bet on the company. The window to make it cleanly is open now, while the impact is still ahead of you.
What this means if you're a long-tenured employee approaching retirement
If you've been at the company a long time and retirement is close, you carry a specific version of this risk. The concentrated position you built during the dominance years now has a job to do — it needs to help fund retirement income. And it's being asked to do that during the exact years the underlying business is absorbing competitive pressure.
If your retirement plan assumes this stock will keep performing the way it did at its peak, that plan deserves another look. Not because the company is in trouble, but because a plan built on dominance-era assumptions is being handed a transition-era reality. The earlier you revisit it, the more options you still have. Wait, and the paths that keep your financial plan and portfolio on track narrow at the same time.
Waiting until the erosion shows up in reported earnings means deciding after the stock has already repriced and after your best options have narrowed. The step worth taking now is having your concentrated position reviewed while the impact is still a forecast.
Pro-Tip: A biosimilar competing with your company's flagship drug is a planning trigger, not a prediction about where the stock goes tomorrow. The question worth asking now — while the window is open and the impact is still ahead — is how much of the household's financial future should remain exposed to a multi-year competitive transition that is now confirmed rather than hypothetical.
If you'd like to explore whether ongoing financial planning and investment management make sense for your situation, you can schedule an intro call here:
Common Questions
Should I sell my pharma company stock when a biosimilar enters the market?
There's no single right answer, because the right answer depends on how much of your total net worth sits in that one stock, your tax situation, and how your household plans to use this money. "Wait and watch it grow" may not work the way it has in the past. The more useful frame isn't sell or hold — it's deciding how much exposure to a confirmed multi-year competitive transition is appropriate for your household, and then addressing it while the impact is still a forecast rather than a reported result. That's a decision worth making with someone who can see your full picture.
How does biosimilar competition typically affect a pharmaceutical company's stock price?
It rarely hits all at once or on the approval date. Market share erosion and pricing pressure build steadily over the quarters after a competitor enters. The stock tends to reprice to reflect a lower forward earnings estimate — the market's revised view of future profits — both before and during the period in which that impact becomes visible in reported results. The practical consequence is that by the time the erosion is obvious in the earnings numbers, much of the repricing has already happened.
How should I think about concentrated pharma stock when my company's drug is losing market share?
Separate two things that often get blended together. One is the one-time tax cost of reducing the position. The other is the recurring, multi-year risk of staying concentrated through a competitive transition. A high tax cost is a real consideration, but it isn't the same as a reason to hold indefinitely. The cleaner way to approach it is as a question about household exposure — how much of your financial future should depend on an outcome you can't control — addressed while you still have the full range of options available.
This blog was written by Jeremy Bohne, Principal & Founder of Paceline Wealth Management. Paceline is a fee-only investment advisor serving clients in the Boston area, and on a remote basis throughout the country. Paceline specializes in helping tech and biotech leaders, business owners, physicians, and those seeking financial planning services.