Mistras to Be Acquired by H.I.G. Capital for $20.35 a Share, About $866M Enterprise Value

Affiliates of H.I.G. Capital agreed on 17 September 2026 to buy Mistras Group (NYSE: MG) for $20.35 per share in cash, an enterprise value of about $866 million including debt, Mistras announced on 18 September 2026 from Princeton Junction, New Jersey. The company says it expects to close in late 2026 or early 2027. A 40-day go-shop, which lets Mistras court rival bidders, runs until 27 October 2026.

Mistras describes itself as a provider of technology-enabled industrial asset integrity and laboratory testing solutions. The terms below come from the company's press release and its Form 8-K.

What are the terms of the Mistras deal?

H.I.G. affiliates will pay $20.35 per share in cash, without interest, for each Mistras share. The merger agreement is dated 17 September 2026 and is between Mistras, Athena Purchaser, LLC and Athena Merger Sub, Inc. The 8-K says the two Athena entities are controlled by funds affiliated with H.I.G. Capital.

Mistras's board unanimously approved the transaction, according to the press release.

Is $20.35 a share the same as the $866 million?

No. The $20.35 is what each shareholder receives. The $866 million is an enterprise value, which adds debt to the equity price. It is not the check written to stockholders. Neither the press release nor the 8-K states a total equity value, so this article does not calculate one.

The gap matters because the buyer takes on or refinances Mistras's borrowing. At 30 June 2026, Mistras reported gross debt of $172.1 million, and a non-GAAP net debt figure of $150.1 million. The 8-K says H.I.G.'s financing is meant to fund the merger consideration, repay certain existing Mistras debt, and pay fees and expenses. The same distinction between a headline number and the number that actually changes hands appears in startup rounds; see Round Size vs Cumulative Funding.

What premium do shareholders get?

The press release gives the premium against two averages, not against the last closing price. The company says $20.35 is about 8% above the 30-day volume-weighted average price and 13% above the 90-day average, both for the period ended 17 September 2026. It also says the price is inclusive of 61% price appreciation since 31 December 2025.

Those are company-chosen baselines. The release does not state a premium to the last close, so readers comparing the offer with the share price on a given day need to do that math themselves.

What approvals does the Mistras deal still need?

Four things have to happen before the deal closes, according to the 8-K:

1. Stockholder vote. Adoption by holders of a majority of the outstanding shares entitled to vote.
2. Regulatory clearance. Expiry or termination of the Hart-Scott-Rodino waiting period and receipt of certain other required regulatory approvals. The filing does not name the other regulators.
3. No blocking order or law preventing the merger.
4. Customary conditions: accurate representations, material compliance with covenants, and no Company Material Adverse Effect.

Mistras says it will file a preliminary proxy statement on Schedule 14A for a special stockholder meeting. That document is where the background of the sale and any competing interest would normally be described.

How much of the vote is already committed?

Holders of about 31% of Mistras's common stock have already agreed to vote yes. The 8-K says each director and named executive officer, plus certain other stockholders, signed voting and support agreements with the buyer. They agreed to vote for the merger and against competing proposals.

Those agreements fall away in set circumstances, including a valid termination of the merger agreement or an amendment that reduces the consideration. A 31% block does not decide a majority vote by itself, but it starts the count well ahead.

What is the go-shop and what does it cost to walk away?

A go-shop allows the seller to keep looking for a better offer after signing. Mistras's board, assisted by its financial adviser Baird, may solicit and consider alternative proposals until 11:59 p.m. Eastern on 27 October 2026. The company says it does not plan to disclose developments during that period unless the board decides disclosure is required or appropriate.

After the window closes, customary no-shop restrictions apply, subject to fiduciary exceptions. The 8-K sets out the break fees:

The 8-K states these amounts as approximate, and the reduced go-shop fee is expressed as a percentage rather than a dollar figure.

How is the deal financed?

The merger is not subject to a financing condition, so the buyer cannot walk away just because lenders fall through. The 8-K says H.I.G. Middle Market LBO Fund IV, L.P. gave an equity commitment letter. It also says certain financial institutions have committed to provide debt financing. The same fund gave a limited guarantee of certain buyer obligations, including the parent termination fee, subject to limits.

The filing does not name the lenders or give the size of the debt or equity commitments.

What happens to Mistras executives and employee equity?

The 8-K discloses cash retention bonuses for four executives, under Item 5.02. Half vests at closing and half 12 months later, and the bonuses vest in full on a termination without Cause or a resignation for Good Reason. For more on reading that item, see How to Read an 8-K Item 5.02.

Equity awards are cashed out at closing, whether vested or not. Restricted stock units are cancelled for $20.35 per share. Options are cancelled for the amount by which $20.35 exceeds the exercise price, and options priced at or above $20.35 receive nothing. Performance units are treated like restricted units, with performance deemed achieved at the greater of target and actual.

Who is H.I.G. Capital, and what business is it buying?

H.I.G. describes itself as a global alternative investment firm. The release says the firm is based in Miami, was founded in 1993, has $75 billion of capital under management, and has invested in more than 400 companies. These are the company's own descriptions.

Mistras serves oil and gas, aerospace and defense, industrials, power generation and transmission, infrastructure, engineering and research customers. Its latest results came before the deal. In the second quarter of 2026 Mistras reported revenue of $193.1 million, up 4.2%, adjusted EBITDA of $25.8 million, and GAAP net income of $7.6 million, or $0.23 per diluted share. Those are company-reported figures.

What's still unclear?

• Equity value. No filing states the total paid to stockholders, only the per-share price and the enterprise value.
• Premium to last close. The release uses 30- and 90-day averages only.
• Regulators. Beyond Hart-Scott-Rodino, the "certain other required regulatory approvals" are not identified.
• Debt terms. Lenders, amounts and pricing of the committed debt financing are not given in the 8-K.
• Rival bids. Mistras does not plan to report go-shop developments unless the board decides it must, so a topping bid could surface only through a later filing or the proxy.

Mistras raised its 2026 outlook on 10 August 2026, five weeks before signing. The board's reasoning for selling at this price is likely to appear in the proxy statement, not in the announcement.