Why Ultralife (ULBI) Stock Jumped 144%: EnerSys Agrees to Acquire Ultralife for $16 a Share

EnerSys agreed on Tuesday, October 27, 2026, to buy Ultralife for $16.00 a share in cash, a 166% premium to Ultralife's closing price on October 26. The deal values the battery maker at about $320 million including debt. The announcement reached the MoveSurge news feed at 16:15:00 ET, after the close, with Ultralife at $6.36. A minute later the stock traded at $15.39, up 141.98%, and ten minutes after the headline it was at $15.53, up 144.18%.

Ultralife had closed the regular session at $6.36, up 5.82%, before the news. On the one-minute chart below, candle closing prices put the stock at $15.41, up 142.30%, after one minute and at $15.52, up 144.03%, after fifteen minutes, slightly different from the trade-by-trade readings above because each candle uses its last trade.

Why Ultralife stopped short of $16

At $15.52 the stock sat $0.48 below the offer, a gap of 3.09%. That gap is what buyers of the stock were paid for waiting until EnerSys hands over the cash and for the risk that the deal falls apart. The companies expect to close in the first quarter of 2027, so the money is several months away, and the deal needs a US antitrust waiting period under the Hart-Scott-Rodino Act to expire and clearance under the UK National Security and Investment Act, according to the filing.

Several terms make a collapse less likely. EnerSys will pay from cash on hand and the offer has no financing condition. Shareholders led by Bradford T. Whitmore, who own about 40.3% of Ultralife, signed a tender and support agreement committing them to tender their shares into the offer. Each side owes the other a $10.3 million termination fee in different cases: Ultralife pays if it walks away for a better offer, and EnerSys pays if antitrust or national security approvals block the deal or if it fails to close once the conditions are met.

What EnerSys is buying

Ultralife makes rechargeable and non-rechargeable batteries, battery systems and accessories, mostly for military radios and other specialized equipment. It reported $191 million of revenue in fiscal 2025, employs more than 700 people and is based in Newark, New York. At about $320 million, EnerSys is paying roughly 1.7 times that revenue. EnerSys said the deal adds batteries built on several chemistries and gives it licensed factory capacity to scale up its own liquid reserve battery, and that the combined defense business is designed to comply with US sourcing rules on a "foreign entity of concern." EnerSys expects $15 million to $20 million of yearly cost savings within 18 months of closing.

EnerSys stock closed at $174.17 on Tuesday, up 2.83%, before the deal was announced after the bell.

What happens next

1. Within 10 business days of October 27: an EnerSys subsidiary must start the tender offer for all Ultralife shares.
2. 25 business days after it starts: the offer is first scheduled to expire, at 5:00 p.m. New York time, and can be extended in steps of up to 10 business days if a condition is still open.
3. First quarter of 2027: the companies' expected closing date.
4. April 27, 2027: the outside date, after which either side can end the agreement, with two possible 60-day extensions if only regulatory approvals are missing.

Ultralife also agreed to seek, at EnerSys's choice, either consent from its partners in an Indian joint venture or a sale of its stake in it. That step is not a condition of the offer. EnerSys will repay Ultralife's bank debt when the merger closes.