What's Driving Terns Pharmaceuticals' Recent Surge

Key Takeaways

• Terns Pharmaceuticals (NASDAQ: TERN) is being acquired by Merck for $53 per share in an all-cash deal valued at approximately $6.7 billion, driven by TERN-701's potential.
• Multiple shareholder rights law firms have launched investigations into the acquisition, alleging potential breaches of fiduciary duty and an unfair price for public shareholders.
• Investors should understand the implications of these class action investigations, including the potential for increased disclosures or, less commonly, an improved offer.

What's Driving Terns Pharmaceuticals' Recent Surge?

Terns Pharmaceuticals (NASDAQ: TERN) has been a significant mover in the biotech sector, with its stock price experiencing a notable surge, particularly in the wake of the announced acquisition by pharmaceutical giant Merck & Co. The deal, valued at approximately $6.7 billion, will see Merck pay $53 per share in cash for all outstanding Terns shares. This represents a 6% premium over Terns' closing price on Tuesday, March 24, 2026, and a substantial 50% premium to the stock's low point in January, when takeover speculation first began to build.

The primary catalyst for this acquisition is Terns' promising leukemia treatment, TERN-701. This investigational oral allosteric BCR-ABL1 tyrosine kinase inhibitor is currently in Phase I/II trials for chronic myeloid leukemia (CML), a slow-growing blood cancer. Merck's move is a strategic one, aimed at bolstering its oncology pipeline as its blockbuster cancer immunotherapy, Keytruda, faces patent expiration in 2028. Keytruda currently accounts for nearly half of Merck's annual sales, making pipeline diversification critical.

Terns' stock responded positively to the news, trading at $52.80 as of March 25, 2026, up 5.60% on the day, nearing its 52-week high of $52.88. This reflects investor confidence in the deal's completion, which is expected in the second quarter of 2026, subject to customary conditions including a tender offer to Terns' stockholders. The acquisition is a clear signal of the high value placed on TERN-701's potential to become a multi-billion-dollar drug, potentially challenging existing treatments like Novartis' Scemblix.

Why Are Shareholder Law Firms Investigating the Merck Deal?

Despite the apparent premium offered by Merck, several prominent shareholder rights law firms have swiftly launched investigations into the acquisition of Terns Pharmaceuticals. On March 25, 2026, firms such as Monteverde & Associates PC, Ademi LLP, and Halper Sadeh LLC announced their probes into the transaction. These investigations typically center on allegations of potential breaches of fiduciary duty by Terns' board of directors and concerns that the $53 per share offer may not represent a fair price for public shareholders.

These M&A class action investigations are a common occurrence in significant corporate takeovers. The firms are scrutinizing whether Terns' board conducted a thorough and independent sales process, explored all strategic alternatives, and ultimately secured the best possible value for its shareholders. They will examine factors such as the fairness of the valuation, potential conflicts of interest among insiders, and the presence of deal protection clauses that might deter competing bids.

For instance, Ademi LLP specifically highlighted that "Terns insiders will receive substantial benefits as part of change of control arrangements" and that the transaction agreement "unreasonably limits competing transactions for Terns by imposing a significant penalty if Terns accepts a competing bid." These types of clauses, often referred to as "break-up fees" or "termination fees," are standard in M&A deals but can become a point of contention if they are perceived as excessively restrictive or designed to favor a specific buyer. The goal of these investigations is to ensure transparency and fairness, potentially leading to increased disclosures or, in some cases, an improved offer for shareholders.

Is the $53 Per Share Offer Truly Undervalued?

The core of the shareholder investigations revolves around whether the $53 per share cash offer from Merck truly represents the maximum value for Terns Pharmaceuticals. While the offer includes a 6% premium to the prior day's close and a 31% premium to Terns' 60-day volume-weighted average stock price, some analysts and market observers suggest the company's lead asset, TERN-701, might warrant a higher valuation.

Analysts from William Blair, for example, publicly questioned Merck's offer, stating it "does not fully capture the potential of TERN-701." They even suggested that "another bidder could emerge with a more attractive offer." RBC Capital Markets echoed this sentiment, viewing Merck's decision to acquire Terns before full dose escalation data as a sign of high confidence in the asset, but also noting that the current price "opens the door for competing bids from other potential acquirers" like AbbVie or Bristol Myers Squibb. These firms estimate TERN-701 could achieve unadjusted peak sales exceeding $4 billion, a significant contribution to Merck's pipeline as it prepares for Keytruda's patent cliff.

Furthermore, a look at recent analyst price targets prior to the acquisition announcement shows a median target of $55.00, with some targets reaching as high as $60.00. Citizens set a target of $57.00 on December 11, 2025, while HC Wainwright & Co. and Oppenheimer had targets of $60.00 and $58.00 respectively on December 9, 2025. While the $53 offer is close to some of these targets, it falls short of others, particularly given the "unprecedented" clinical profile described by William Blair analysts for TERN-701. This discrepancy fuels the argument that Terns shareholders might be leaving money on the table.

What Do "Breaches of Fiduciary Duty" and "Unfair Price" Entail?

In the context of a merger or acquisition, allegations of "breaches of fiduciary duty" and "unfair price" are serious claims that suggest Terns' board of directors may not have acted solely in the best interests of its shareholders. Fiduciary duty legally obligates board members to act with loyalty and care, ensuring that transactions benefit the company and its shareholders, not just a select few. A breach could occur if the board failed to adequately shop the company, rushed the sale process, or had undisclosed conflicts of interest.

An "unfair price" claim often arises when the offer price is perceived to be below the company's intrinsic value or what could have been achieved through a more competitive bidding process. This is particularly relevant for a biotech firm like Terns, where the value is heavily tied to the future potential of its drug pipeline, such as TERN-701. If the board accepted an offer that undervalues a promising asset, or if the process was structured to deter higher bids, it could be seen as a failure to maximize shareholder value.

The investigations will scrutinize the "change of control arrangements" for Terns insiders, which often include accelerated vesting of stock options or other compensation tied to the acquisition. While these are common, if they are deemed overly generous or influenced the board's decision-making to the detriment of public shareholders, it could constitute a breach. Similarly, deal protection clauses, such as significant termination fees for accepting a superior proposal, will be examined to ensure they didn't unduly restrict the board's ability to consider other offers, thereby limiting the potential for a higher price.

What Role Do Insider Trades Play in These Investigations?

Insider trading activity, particularly around a significant corporate event like an acquisition, often draws scrutiny from shareholder rights firms and can become a focal point in class action investigations. For Terns Pharmaceuticals, the Q1 2026 summary of corporate insider trades reveals a notable pattern: 0 purchases and 10 sales by insiders. While the overall buy/sell ratio of 1.12 indicates net buying in terms of shares, this is largely due to option exercises (M-Exempt transactions) rather than open market purchases.

Specifically, Amy L. Burroughs, Terns' Chief Executive Officer, engaged in several transactions on March 16, 2026. She exercised options to acquire 14,583 shares at a price of $4.64 per share. Critically, on the same day, she disposed of 11,813 shares at $46.57 and another 2,770 shares at $47.30. These sales occurred just days before the Merck acquisition was officially announced on March 25, 2026, at $53 per share. While these transactions are not inherently illegal and often represent pre-scheduled vesting or liquidity events, their timing relative to the acquisition announcement and the significant price difference can raise questions.

Shareholder attorneys will likely examine whether these insider sales, particularly those at prices substantially below the final acquisition offer, suggest that insiders may have had knowledge of the impending deal or its terms, and whether their actions were consistent with maximizing value for all shareholders. The optics of insiders selling shares at prices well below the eventual acquisition price can fuel arguments that the board, including its executives, may have been too eager to accept the Merck offer without fully exploring higher valuations or ensuring a more robust sales process.

What Actions Can Terns Shareholders Take?

For current shareholders of Terns Pharmaceuticals, understanding their options in the face of these M&A class action investigations is crucial. The primary goal of these lawsuits is to ensure that the acquisition process was fair and that shareholders receive the maximum possible value for their shares. While the Merck deal is structured as a tender offer, meaning shareholders will individually decide whether to tender their shares, the investigations aim to influence the overall terms.

Shareholders who believe the $53 per share offer is inadequate or that the board breached its fiduciary duties can contact the investigating law firms. These firms typically operate on a contingency fee basis, meaning shareholders incur no out-of-pocket costs unless a recovery is made. While an outright cancellation of the merger is rare, these investigations can lead to several outcomes. The most common result is often an agreement for Terns to provide additional disclosures to shareholders, offering more transparency into the valuation process and the board's decision-making.

Less frequently, and often as a result of significant legal pressure or the emergence of a competing bid, the acquiring company may agree to increase its offer price. This happened in other M&A cases where initial offers were challenged. Shareholders should carefully review all proxy materials and tender offer documents when they become available, as these will contain detailed information about the transaction and any potential legal developments. Staying informed and, if concerned, engaging with legal counsel specializing in shareholder rights is the best course of action to protect one's investment in Terns.

The Merck acquisition of Terns Pharmaceuticals presents a clear strategic move for the pharma giant, but the ongoing shareholder investigations underscore the importance of transparency and fairness in M&A deals. Investors should remain vigilant, monitoring developments closely as the transaction progresses towards its expected Q2 2026 close. The outcome of these probes could influence not only the final terms for Terns shareholders but also set precedents for future biotech acquisitions.

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