Ultralife Stock Soars 145%: EnerSys Pays a 166% Premium in a $320 Million Buyout

Ultralife Corporation (NASDAQ: ULBI) stock soared about 145% on Wednesday, October 28, 2026, after EnerSys (NYSE: ENS) agreed to buy the military battery maker for $16.00 a share in cash — a 166% premium — in a deal valued at about $320 million. The stock closed Tuesday at $6.36 and traded around $15.60 on Wednesday, just below the $16.00 offer price, on pace for its best trading day ever.

What happened

EnerSys, a global maker of stored-energy systems for industrial, infrastructure and defense customers, announced a definitive agreement to acquire Ultralife for $16.00 per share in cash. The price is a 166% premium to Ultralife's unaffected closing price on Monday, October 26, and the transaction carries an enterprise value of approximately $320 million, including assumed net debt. Ultralife, headquartered in Newark, New York, makes rechargeable and non-rechargeable batteries, battery systems and accessories used in military communications and other specialized applications.

The market reaction was immediate. Ultralife shares surged roughly 146% to about $15.65 during Wednesday's session, which Barron's, citing Dow Jones Market Data, described as on pace for the stock's largest one-day percentage gain on record, dating back to 1992. Before the deal, Ultralife's entire market value was only about $106 million. EnerSys shares, by contrast, were little changed near $174.

Why it's blowing up

Premiums of 166% are rare, and that is the headline. EnerSys is not buying Ultralife for its recent earnings — the company recorded a loss over the past year — but for its position in defense power. EnerSys said the deal will accelerate its drone and counter-drone systems, expand its battery technologies and add U.S.-based manufacturing capacity for specialized, FEOC-compliant batteries. The combined company will target munitions, soldier power, drones, counter-drone systems and autonomous platforms for the U.S. Department of War and allied forces.

"We will be better positioned to support the U.S. Department of War and allied forces with leading-edge, cost-effective technologies for the increasingly electrified battlefield of the future," EnerSys CEO Shawn O'Connell said in the announcement. Ultralife brings more than 700 employees across the U.S., Canada, the U.K. and China, a patent portfolio in multi-chemistry batteries, and $191 million of revenue in fiscal 2025.

Key facts

• Offer: $16.00 per share in cash, a 166% premium to Ultralife's October 26 close.
• Deal value: About $320 million in enterprise value, including net debt.
• Stock move: Ultralife rose about 145% on Wednesday, from a $6.36 close on Tuesday to around $15.60 — just under the offer price, a typical gap for a pending cash deal.
• Funding: EnerSys will pay with cash on hand; there is no financing contingency.
• Structure: An EnerSys subsidiary will launch a tender offer for all outstanding Ultralife shares, followed by a merger. Both boards approved the deal unanimously.
• Synergies: EnerSys expects $15 million to $20 million in annual run-rate cost synergies within the first 18 months, and expects the deal to add to adjusted earnings per share in roughly the same period.
• Closing: Expected in the first quarter of calendar 2027, subject to a majority of shares being tendered and to regulatory approvals, including antitrust and national-security review.

What's next

The tender offer comes next. Ultralife shareholders who tender will receive $16.00 in cash if the deal closes; the stock trading slightly below that level reflects the time and approval risk between now and closing, not a judgment on the price. As is routine in buyouts, at least one shareholder law firm has already announced an investigation into whether the Ultralife board ran a fair process — a standard step that rarely changes deal terms. If the required approvals land, Ultralife will be delisted and become part of EnerSys in early 2027, and Wednesday's record one-day jump will stand as the stock's defining session.

Sources: Barron's, Business Wire (EnerSys announcement), KuCoin / Benzinga, TipRanks. This article is news reporting, not investment advice.

FAQ

Why did Ultralife stock jump 145% today?

EnerSys agreed to buy Ultralife for $16.00 a share in cash, a 166% premium to its October 26 close, so the stock repriced almost immediately toward the takeover price.

How much is EnerSys paying for Ultralife?

$16.00 per share in cash, valuing the deal at about $320 million in enterprise value including net debt, funded from EnerSys' cash on hand.

When will the Ultralife buyout close?

EnerSys expects the deal to close in the first quarter of calendar 2027, after a tender offer wins a majority of shares and regulatory approvals are received.

What does Ultralife make?

Ultralife makes rechargeable and non-rechargeable batteries and battery systems, mainly for military communications and specialized defense uses such as soldier power and drones.