Is the SIEGEL TAVR valve approved for sale?

No. The company explicitly states the SIEGEL system is an investigational device not yet approved for commercial distribution in any country. It is being evaluated in the STAR pivotal trial in up to 1,025 patients with severe, symptomatic aortic stenosis, with the goal of obtaining FDA premarket approval.

What is the financial impact on Boston Scientific's earnings?

Management expects the investment to be immaterial to adjusted earnings per share in 2026. The filing does not provide longer-term financial projections, and the call option's exercise timing is uncertain, so the longer-term impact depends on milestone achievement, regulatory outcomes, and future TAVR net sales.

What happens if Boston Scientific does not exercise the call option?

If BSX does not make required additional payments, does not exercise the call option within the applicable period, or the call option does not close after exercise, its equity interest in MiRus is forfeited or reduced by approximately 75%, or exchanged for an interest in TAVR-Structural Heart NewCo, depending on circumstances. This creates meaningful downside risk to the $1.5 billion already invested.

Why is Boston Scientific pursuing this investment?

BSX states it wants a differentiated TAVR system in its portfolio as aortic stenosis diagnosis grows. The SIEGEL valve is pitched as having a nickel-free rhenium alloy frame, radial strength greater than cobalt or titanium, pre-mounted balloon delivery, and an 8 French expandable sheath about 50% smaller than current commercial TAVR delivery sheaths. These are company claims tied to early clinical data and remain subject to pivotal trial results.

BSX 8-K SEC Disclosure — May 18, 2026

Q: How much is Boston Scientific committing to MiRus in total?

BSX has paid $1.5 billion in cash for a 33.75% equity stake, on top of a previously paid $100 million. The exclusive call option to acquire the TAVR business requires an additional $3.0 billion in aggregate cash payments, tied to milestones. Total committed capital, excluding post-exercise net-sales payments and any mitral/tricuspid option payments, is roughly $4.6 billion.

01—Abstract

Summary

Summary of the 8-K filed May 18, 2026. Cited figures are marked; the original filing is the authoritative source.

On May 18, 2026, Boston Scientific (BSX) disclosed a strategic investment in MiRus LLC, a privately held developer of cardiovascular and orthopedic technologies.

On May 15, 2026, BSX paid $1.5 billion^a in cash (excluding a previously paid $100 million) for non-voting common equity representing 33.75% of MiRus's fully diluted equity. The investment also grants BSX an exclusive option to acquire, for an additional $3.0 billion in aggregate cash payments tied to clinical and regulatory milestones, 100% of a newly formed subsidiary (TAVR-Structural Heart NewCo) holding MiRus's TAVR assets. The underlying asset is the investigational SIEGEL balloon-expandable TAVR system, which is not approved for commercial distribution and is being evaluated in the STAR pivotal trial of up to 1,025 patients.

The company states the investment is expected to be immaterial to 2026 adjusted EPS. The strategic rationale is to add a differentiated TAVR platform to BSX's structural heart portfolio as aortic stenosis diagnosis grows. Management highlights the device's nickel-free rhenium alloy frame, pre-mounted balloon delivery, and an 8 French expandable sheath that is roughly 50%^b smaller than current commercial TAVR delivery sheaths.

For investors, the key considerations are the total potential commitment of roughly $4.6 billion^c (the $1.5 billion investment plus the $3.0 billion call option, before any additional net-sales-based payments to MiRus), the binary dependence on pivotal trial outcomes and FDA approval, and the downside structure: if BSX does not make required payments or exercise the call option in time, its equity stake is forfeited or reduced by about 75%, or exchanged for an interest in the NewCo entity. The filing contains extensive forward-looking statement cautions.

02—Key points

Key Highlights

BSX paid $1.5 billion in cash (plus a previously paid $100 million) on May 15, 2026 for 33.75% of MiRus's fully diluted non-voting common equity.
An exclusive call option allows BSX to acquire 100% of TAVR-Structural Heart NewCo for an additional $3.0 billion, payable upon MiRus achieving clinical and regulatory milestones.
Total potential commitment is approximately $4.6 billion before any royalty-like payments tied to SIEGEL TAVR net sales if the option is exercised.
Management expects the investment to be immaterial to 2026 adjusted EPS.
The SIEGEL TAVR system is investigational and not approved for commercial distribution; it is in the up-to-1,025-patient STAR pivotal trial.
BSX also holds an exclusive option, exercisable if the call option is exercised, to acquire MiRus's mitral and tricuspid replacement valve assets for an additional payment.
If required payments are missed or the call option is not exercised or does not close, BSX's stake is forfeited or reduced by about 75%, or exchanged for an interest in the NewCo.

03—Questions

Frequently Asked Questions

How much is Boston Scientific committing to MiRus in total?
BSX has paid $1.5 billion in cash for a 33.75% equity stake, on top of a previously paid $100 million. The exclusive call option to acquire the TAVR business requires an additional $3.0 billion in aggregate cash payments, tied to milestones. Total committed capital, excluding post-exercise net-sales payments and any mitral/tricuspid option payments, is roughly $4.6 billion.
Is the SIEGEL TAVR valve approved for sale?
No. The company explicitly states the SIEGEL system is an investigational device not yet approved for commercial distribution in any country. It is being evaluated in the STAR pivotal trial in up to 1,025 patients with severe, symptomatic aortic stenosis, with the goal of obtaining FDA premarket approval.
What is the financial impact on Boston Scientific's earnings?
Management expects the investment to be immaterial to adjusted earnings per share in 2026. The filing does not provide longer-term financial projections, and the call option's exercise timing is uncertain, so the longer-term impact depends on milestone achievement, regulatory outcomes, and future TAVR net sales.
What happens if Boston Scientific does not exercise the call option?
If BSX does not make required additional payments, does not exercise the call option within the applicable period, or the call option does not close after exercise, its equity interest in MiRus is forfeited or reduced by approximately 75%, or exchanged for an interest in TAVR-Structural Heart NewCo, depending on circumstances. This creates meaningful downside risk to the $1.5 billion already invested.
Why is Boston Scientific pursuing this investment?
BSX states it wants a differentiated TAVR system in its portfolio as aortic stenosis diagnosis grows. The SIEGEL valve is pitched as having a nickel-free rhenium alloy frame, radial strength greater than cobalt or titanium, pre-mounted balloon delivery, and an 8 French expandable sheath about 50% smaller than current commercial TAVR delivery sheaths. These are company claims tied to early clinical data and remain subject to pivotal trial results.

04—Continue

← View all 8-K filings