Mevion Medical Systems

Littleton, MA, USA Healthcare Private

Mevion Medical Systems is the leading provider of compact proton therapy systems for cancer treatment. The company designs and manufactures the MEVION S250 Series, the world's most compact proton therapy systems that eliminate obstacles of size, complexity, and cost. With more installed systems treating patients than any other compact proton therapy manufacturer, Mevion has revolutionized access to proton therapy with innovative technologies including pencil beam scanning and direct beam delivery.

Overview

Company data and valuation marks are estimates and may be incomplete, stale, erroneous, or revised.

Founded

2004

Employees

200–250

Total Funding

$395M

4 rounds

Funding

Total raised $395M across 4 rounds

Funding data and valuation marks are estimates and may be incomplete, stale, erroneous, or revised.

Last updated 06-25-2026

Latest Round

Type

Series F

Date

2018

Amount

$150M

Valuation

Lead Investors

YuanMing Capital
DateRoundAmount RaisedValuationLead Investors
2018 Series F $150M YuanMing Capital
2015 Series E (China financing) $200M HOPU Investments, YuanMing Capital
2012 Late stage $45M ProQuest Investments

Prominent Investors

yuanmingcap.cn everbright.com

Leadership

  • Dr. Tina Tianning Yu

    Chief Executive Officer & President

  • Dr. Lawrence Tian

    Chairman

  • Curt Kienast

    Chief Operating Officer

    LinkedIn

Competitors

Competitor list is illustrative and may be incomplete, stale, or erroneous.

  • IBA (Ion Beam Applications)

    Belgian proton therapy leader with comprehensive cyclotron, treatment room, and radiopharma offerings; EUR 498.2M revenue in 2024

  • Hitachi

    Japanese conglomerate with superconducting beamline patents and strong Asia-Pacific regional presence in proton therapy

  • Sumitomo Heavy Industries

    Japanese manufacturer with compact cyclotron technology and energy-efficient delivery models; founded 1888

  • Varian Medical Systems

    Siemens Healthcare subsidiary providing comprehensive radiation therapy and proton therapy solutions

  • Advanced Oncotherapy

    Develops compact linear proton accelerators (LIGHT) to lower costs and decentralize proton therapy access

  • ProTom International

    Proton therapy system manufacturer competing in compact and traditional system markets

Mevion Medical Systems Investment FAQ

Public status and buying access

No. Mevion Medical Systems is a private company and does not have a public stock ticker or trade on a public stock exchange. Its shares are generally held by founders, employees, investors, and other private shareholders. Buyers and sellers may be able to transact in Mevion Medical Systems shares through private secondary transactions, but any transaction depends on share availability, buyer and seller agreement, transfer restrictions, company approval rights, and any applicable right of first refusal. There is no guarantee that Mevion Medical Systems will complete an IPO or other liquidity event.

Yes, it is sometimes possible to buy Mevion Medical Systems shares pre-IPO through private secondary transactions. This depends on finding a willing seller, company approval, and satisfying any transfer restrictions or rights of first refusal.

Buyers interested in buying Mevion Medical Systems shares on the secondary market typically do so through SetterVC and other secondary-market platforms, subject to eligibility requirements, share availability, transfer restrictions, and issuer approval. Buyers may need to satisfy sophistication, accreditation, institutional, platform, regulatory, or other eligibility requirements before participating. Once eligible, buyers may be able to view listings, make bids, and work with a licensed broker through the transaction process. Buyers should ensure they have appropriate legal and financial advisors guiding them before completing any transaction.

Valuation and funding

Mevion Medical Systems's latest disclosed funding round was a Series F round in 2018. The round raised approximately $150M, with YuanMing Capital listed as disclosed lead or major investors. Primary funding rounds are different from secondary transactions: in a primary round, capital goes to the company, while in a secondary transaction, investors buy existing shares from current shareholders. Funding-round data reflects publicly reported or collected information and may be incomplete.

Mevion Medical Systems has raised approximately $395M in disclosed funding across 4 rounds. These figures reflect primary capital raised by the company and do not include every possible secondary transaction, undisclosed round, debt facility, or private transfer. Reported funding totals can change as new rounds are announced or older round details are corrected. Eligible users can use SetterVC to track Mevion Medical Systems's funding history alongside private-market activity where available.

Mevion Medical Systems's disclosed investors include yuanmingcap.cn and everbright.com. Investor lists are based on public reporting, company announcements, and collected funding-round data, and may be incomplete. Participation in a prior funding round does not mean those investors are currently buying or selling shares. On SetterVC, eligible users can review Mevion Medical Systems's funding history, valuation history, and private-market activity alongside other venture-backed companies.

Market context

Mevion Medical Systems's most-cited competitors include IBA (Ion Beam Applications), Hitachi, Sumitomo Heavy Industries, Varian Medical Systems, Advanced Oncotherapy and ProTom International. Investors often compare these companies by sector, product focus, valuation, funding raised, growth signals, investor base, and private-market activity.

Secondary-market demand for Mevion Medical Systems shares can be affected by company performance, revenue growth, profitability, funding history, valuation, investor interest, sector momentum, public-market conditions, expected timing of a liquidity event, and the availability of shares for sale. Demand can also be affected by transfer restrictions, company approval rights, right of first refusal processes, limited information, and the price expectations of buyers and sellers. Strong demand does not guarantee strong pricing, liquidity, or investment returns. Weak demand does not necessarily reflect the company's long-term prospects. Demand signals should not be treated as a recommendation or prediction of investment performance. Buyers and sellers should treat demand signals as informational and conduct their own diligence before transacting.

Selling and transaction mechanics

Sellers often rely on intermediaries and platforms, such as SetterVC and other secondary-market platforms, to identify potential buyers. The exact process varies by company and transaction, but sellers often begin by confirming their ownership, desired price, transferability, and any company approval or notice requirements. If the seller agrees with a buyer on acceptable price and terms, the company may need to be notified through a share transfer notice or similar process. If a right of first refusal, company approval right, or other transfer restriction applies, the seller may need to wait until that process is completed. The parties may then execute a purchase and sale agreement, complete required transfer documentation, and close if all required conditions are satisfied. Sellers should always seek proper legal and financial advice before completing the transaction.

Yes, current and former Mevion Medical Systems employees, early investors, and other existing shareholders may be able to sell vested shares before an IPO through a private secondary sale. This is not automatic; it depends on whether the shareholder has transferable shares, whether there is buyer demand, and whether the company's governing documents permit the transfer. Many companies require prior notice, company approval, or a right of first refusal before shares can be sold. Sellers should also seek proper legal and financial advice before proceeding.

A Mevion Medical Systems secondary transaction usually involves an existing shareholder selling shares to a buyer before a public listing. The buyer and seller typically agree on price, number of shares, share class, and closing conditions. The seller may then need to notify Mevion Medical Systems through a share transfer notice or similar process. If Mevion Medical Systems or existing investors have approval rights, transfer restrictions, or a right of first refusal, those steps may need to be completed before the transfer can close. The parties typically enter into a purchase and sale agreement, complete any required transfer documentation, and close only if the necessary conditions are satisfied. Timing and certainty can vary by company and transaction.

In most private secondary transactions, parties commonly use a purchase and sale agreement that outlines price, terms, and conditions. They may also use share transfer documentation, often a stock transfer notice, share transfer notice, transfer instruction, or similar document, along with any required company approval or right of first refusal materials. Proof of ownership, such as a cap table entry, share certificate, brokerage statement, issuer confirmation, or administrator confirmation, may also be important. Buyers often request recent company financials, but private companies may limit disclosure. Since every deal varies, buyers and sellers should consult legal and financial advisors to understand which documents are needed.

Risk, diligence, and investor caution

Buying Mevion Medical Systems shares pre-IPO is risky. Shares are illiquid, no IPO or liquidity event is guaranteed, valuations can change, transfers may require company approval, and private companies may provide limited financial disclosure. Be prepared for total loss. SetterVC and Setter Capital do not provide due diligence, legal, tax, accounting, valuation, or investment advice. Buyers must conduct their own due diligence, verify information, and seek independent legal and investment advice before proceeding.

Private secondary shares are typically illiquid. Unlike public stocks, there is no active public market, so selling them can be difficult and time-consuming. Sales depend on finding a willing buyer and often require company approval. Investors should be prepared to hold the shares for an extended period, with no guarantee of a future sale. Always assess your need for liquidity before investing.

SetterVC and Setter Capital do not provide due diligence, legal, tax, accounting, valuation, or investment advice. Buyers must conduct their own due diligence, including verifying ownership, transferability, legal structure, company approval, and assessing the company's prospects. SetterVC and Setter Capital do not provide advice on whether an investment is good, what price to pay, or what the best bid or ask is. SetterVC and Setter Capital may share documents in some circumstances, but it does not guarantee their accuracy or completeness. Due diligence is essential. Seek legal and investment advice as needed.

Before buying Mevion Medical Systems shares, a buyer should try to review the share class, price per share, implied valuation, transfer restrictions, ROFR process, company approval rights, seller ownership evidence, recent financing or tender-offer information, available financial information, information rights, resale restrictions, tax considerations, and expected liquidity paths. Not all information may be available for a private company. Buyers should confirm available diligence, process details, and information needs with their own legal, tax, and investment advisers.

SPVs carry risks. Examples include the need to confirm the company allows SPV-based transfers, verify that the SPV truly owns the shares or interests it claims to own, and ensure it has not sold more interests than it holds. Due diligence is essential. Seek legal and investment advice as needed.

Forward contracts carry risks. Examples include the seller refusing to transfer the shares at the future date, even if the seller owns them, the seller going bankrupt with creditors claiming the shares, or the seller committing the same shares to multiple parties. Due diligence is essential. Seek legal and investment advice as needed.

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