BSX vs MMSI: Which Is the Better Buy in 2026?
Last updated October 2026
Short answer
BSX is the larger of the two ($64.33B market cap): the incumbent the market prices for continued execution (13.15x forward earnings, beta 0.57). MMSI is the smaller challenger ($5.33B), actually pricier on forward earnings (19.34x): more room to run, but more to prove. The real question is which set of drivers you believe, and whether owning one (or both) leaves you over-concentrated.
BSX vs MMSI: the tie-breaker metrics
Same yardstick, side by side (as of October 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.
| Metric | BSX | MMSI | What it tells you |
|---|---|---|---|
| Market cap | $64.33B | $5.33B | Size. The larger name is the incumbent; the smaller has more room to grow and more to prove. |
| Forward P/E | 13.15 | 19.34 | Valuation on next year's expected earnings, the same yardstick for both. Lower is cheaper for that growth; higher means the market is paying up. |
| Trailing P/E | 17.97 | 36.71 | Valuation on the last 12 months. A big drop from trailing to forward means the market expects earnings to jump, so more growth is already in the price. |
| Beta | 0.57 | 0.51 | Volatility vs the market. Above 1 swings harder than the index; below 1 is steadier. Higher beta means bigger drawdowns to hold through. |
| Price vs 52-week range | 5% of range | 84% of range | Where today's price sits between the 52-week low and high. Near the high is momentum with less margin of safety; near the low is out of favor or a discount, depending on why. |
| Price / book | 2.58 | 3.17 | How much you pay over book value. Very high can signal an asset-light, high-return business or a rich price. |
Reading it: BSX is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.
Before you buy: how BSX and MMSI affect your concentration
The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. BSX and MMSI share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.
This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined BSX and MMSI exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.
What does Boston Scientific Corporation (BSX) do?
Boston Scientific Corporation is a Marlborough, Massachusetts-based medical device company that develops, manufactures, and markets minimally invasive devices used in interventional cardiology, electrophysiology, structural heart, peripheral interventions, endoscopy, urology, neuromodulation, and cardiac rhythm management. It reports through two broad segments: Cardiovascular, which houses the electrophysiology business (led by the Farapulse pulsed field ablation system) and the Watchman left-atrial-appendage closure franchise, and MedSurg, which spans endoscopy, urology, and neuromodulation. The company sells into hospitals and physicians across roughly 130 countries and competes at the leading edge of catheter-based and device-based procedures that substitute for more invasive surgery.
What does Merit Medical Systems (MMSI) do?
Merit Medical Systems designs, manufactures, and markets a broad catalog of single-use and capital medical devices used in minimally invasive procedures. Its business splits into two segments: Cardiovascular (peripheral intervention, cardiac intervention, interventional oncology and spine, and cardiovascular and critical care) and Endoscopy (non-vascular stents, balloon dilators, and related tools for gastroenterologists and pulmonologists). The company sells globally through direct sales forces and distributors, and it has grown trailing revenue to about $1.58 billion, with 2026 guidance of $1.631 to $1.643 billion, driven by a mix of organic volume and frequent product-line acquisitions.
BSX vs MMSI: how do they differ?
Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.
- BSX drivers: Farapulse and the Pulsed Field Ablation Wave; Watchman Franchise Expansion.
- MMSI drivers: Organic growth in interventional devices; Bolt-on acquisitions.
Which fits which kind of investor
A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The most immediate concern is a run of setbacks in 2026. For MMSI, merit competes against far larger and better-capitalized device companies including Boston Scientific, Medtronic, Abbott, Teleflex, Becton Dickinson, and Terumo, which can pressure pricing and share.
BSX or MMSI: which should you pick?
Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick BSX if you believe its drivers more; MMSI if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the BSX and MMSI guides.
BSX vs MMSI: the full fundamentals
BSX. Boston Scientific's trailing P/E of roughly 18x and forward multiple near 13x are far below the sustained premium the stock carried during its high-growth phase. The compression followed a decline of about 55% over the past year, while the S&P 500 rose about 17%, driven by slowing growth, repeated outlook cuts, and the September cybersecurity disruption. Third-quarter results are due October 28, 2026, with consensus near $0.74 to $0.76 of adjusted EPS on revenue of about $5.1 billion, and the analyst mean target of about $59 sits well above the $44.06 share price, so the debate is whether the lower multiple reflects fair concern about decelerating growth or an over-correction.
MMSI. Merit trades around 37 times trailing GAAP earnings but about 19 times forward estimates, because GAAP results carry heavy acquisition amortization that non-GAAP EPS excludes. Q2 2026 revenue of $418.8 million rose 10 percent and non-GAAP EPS of $1.19 beat expectations, prompting management to raise full-year guidance to about 8 percent revenue growth and 11 to 14 percent non-GAAP EPS growth. The 11 covering analysts rate it a buy with a mean target near $102; Q3 results are due October 29, 2026, with consensus EPS near $1.03 on $410 million of revenue.
Headline figures (approximate, October 2026): BSX shows revenue (ttm) ~$21 billion (+7.5% YoY in Q2 2026), revenue (fy 2025) ~$20.1 billion, net income (ttm) ~$3.7 billion (profit margin ~17.5%), adjusted eps (q2 2026) $0.86 vs $0.83 est.; MMSI shows revenue (ttm) ~$1.58B; Q2 2026 up ~10% (9% organic constant currency), market cap ~$5.3B (share price ~$88.81), net income (ttm) ~$146M (profit margin ~9%), p/e ~37x trailing GAAP, ~19x forward.
The bottom line: BSX vs MMSI
BSX and MMSI are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined BSX and MMSI exposure against your real portfolio. It is not an investment adviser.
Wondering how BSX or MMSI fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in Boston Scientific Corporation with AI
Connect the broker you already use and ask Walnut's AI how BSX fits what you actually hold: whether you own it already through a fund, what it would do to your concentration, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
What is the difference between BSX and MMSI?
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Boston Scientific Corporation is a Marlborough, Massachusetts-based medical device company that develops, manufactures, and markets minimally invasive devices used in interventional cardiology, electrophysiology, structural heart, peripheral interventions, endoscopy, urology, neuromodulation, and cardiac rhythm management. Merit Medical Systems designs, manufactures, and markets a broad catalog of single-use and capital medical devices used in minimally invasive procedures. They show up together because they share investment themes, but they are different businesses, so the better fit depends on which thesis you are expressing.
Is BSX or MMSI the better stock?
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Neither is universally better. BSX is the larger incumbent; MMSI is the smaller challenger and looks pricier on forward earnings. Walnut is informational, not investment advice. Compare what each does, the tie-breaker metrics above, and the risks, then decide which fits your thesis and what you already own.
Which is cheaper, BSX or MMSI?
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On forward P/E (as of October 2026), BSX trades at 13.15x and MMSI at 19.34x, so BSX is the cheaper of the two on next year's expected earnings. A lower multiple is not automatically the better buy: a richer valuation can be justified by faster growth, and a lower one can reflect real risk. Weigh the multiple against how fast each business is compounding.
Should you own both BSX and MMSI?
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Because they share themes, owning both concentrates you in that theme. That can be intentional (a focused bet) or accidental (less diversification than it looks). Walnut can show your combined exposure across both, and whether adding either over-concentrates you, before you buy.
What are the risks of BSX vs MMSI?
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BSX: The most immediate concern is a run of setbacks in 2026. Management lowered its profit outlook in July on weaker Watchman demand and US electrophysiology share losses, then in September said a cybersecurity incident had disrupted manufacturing and order shipments and that it was unlikely to meet its third-quarter and full-year sales and adjusted earnings forecasts. In October it recalled 262,686 Imager II angiographic catheters because the tip may fracture or detach during use, a reminder of the product-recall and safety-signal risk inherent to medical devices. Competition is intensifying as Medtronic and Johnson and Johnson scale their own pulsed field ablation systems, which could further erode Boston Scientific's early PFA share and pressure pricing. Brokers including Baird, Truist and Mizuho trimmed price targets in mid-October 2026. Foreign exchange swings, hospital capital-spending cycles, reimbursement or regulatory changes, about $12.6 billion of debt, and integration risk from the company's acquisition strategy each add uncertainty. MMSI: Merit competes against far larger and better-capitalized device companies including Boston Scientific, Medtronic, Abbott, Teleflex, Becton Dickinson, and Terumo, which can pressure pricing and share. Tariffs weighed on gross margin by roughly 120 basis points in early 2026, and input-cost and currency volatility remain ongoing headwinds. The growth model leans on continued acquisitions, so a slowdown in deal flow or a poorly integrated deal could stall the story. The stock also trades at a premium med-tech multiple (about 37 times trailing GAAP earnings) after a roughly 21 percent three-month rally, which leaves little room for execution missteps when Q3 results arrive on October 29, 2026. Year-to-date free cash flow fell 14 percent through June, and total debt is about $748 million, including convertible notes due 2029. Regulatory, reimbursement, and product-recall risks are inherent to the medical device industry.
Walnut is informational, not investment advice. This page is descriptive and not a recommendation to buy or sell BSX or MMSI; figures are approximate and dated (as of October 2026). Verify current data before investing.