The single most expensive component in an electric vehicle is the battery, and the cell is the heart of the battery. So one of the defining strategic choices an automaker makes is whether to buy cells from suppliers or to build them itself. GM’s answer, spelled out across its filings, is a hybrid: a jointly owned manufacturer called Ultium Cells.

In its most recent Form 10-K, filed January 27, 2026 for the year ended December 31, 2025, GM describes how the venture fits its product strategy. The filing states that the company’s EV portfolio “takes advantage of integrated supply chain development, including battery cell production from Ultium Cells” — and it goes further than earlier disclosures by naming the plants. The cells, the 10-K says, come from facilities “in Warren, Ohio and Spring Hill, Tennessee.” The filing is on sec.gov, indexed by SEC filings.

“Our EV portfolio takes advantage of integrated supply chain development, including battery cell production from Ultium Cells Holdings LLC (a joint venture with LG Energy Solution) in plants in Warren, Ohio and Spring Hill, Tennessee.”— General Motors Co., Form 10-K (FY2025) source

Read that sentence carefully and the structure of the strategy is all in it. “Integrated supply chain development” is the thesis: GM is not treating cells as a commodity to be purchased on the open market but as a link in a chain it is helping build. “Ultium Cells Holdings LLC” is a separate legal entity — a holding company — not a GM division, which is the legal signature of a joint venture rather than a wholly owned plant. And “(a joint venture with LG Energy Solution)” names the partner: one of the world’s largest and most experienced lithium-ion cell makers. GM did not go it alone, and it did not simply sign a supply contract. It co-owns the factory.

The financial statements make the co-ownership concrete in a way the marketing language does not. Elsewhere in GM’s filings, Ultium Cells is described as “an equally owned joint venture with LG Energy Solution (LGES),” and the equity earnings from it are “presented in Automotive and other cost of sales as this entity is integral to the operations of our business by providing battery cells for our EVs.” That accounting treatment is telling. A company reports equity income or loss from a joint venture it co-owns — its share of the venture’s profit or loss flows onto GM’s own income statement. A company that merely buys cells records a purchase, an expense, not a share of a partner’s results. The presence of equity earnings tied to Ultium is the financial fingerprint of a true co-owned business.

Why take on cell manufacturing at all? Three reasons recur in the logic of vertical integration. First, supply security: cells were the chokepoint of the EV ramp, and owning capacity insulates you from a supplier’s other customers. When demand outran cell supply industry-wide, automakers without their own capacity waited in line; an owner does not. Second, cost: at scale, capturing the manufacturing margin and tuning the chemistry to your own packs lowers the per-kWh cost that dominates EV economics — and per-kWh cost, more than almost anything else, decides whether an EV can be sold profitably. Third, roadmap control: co-owning the plant means the automaker has a seat at the table on what chemistry and cell format come next, rather than accepting whatever a supplier chooses to offer.

The joint-venture structure is the compromise that makes all three reachable. Building cells from scratch is enormously capital-intensive — the Warren and Spring Hill plants represent billions of dollars of investment — and it requires deep electrochemistry and high-volume manufacturing expertise that automakers historically lacked. Partnering with an established cell maker splits the capital, imports the manufacturing know-how, and still gives the automaker ownership and influence. “Equally owned” is the balance struck: neither party is a mere vendor to the other, and decisions are shared. That GM places the venture’s results in “cost of sales” rather than treating it as a passive financial investment underscores how operationally entangled the two companies are — the venture exists to feed GM’s lines.

The plant locations are worth noticing too. Warren, Ohio and Spring Hill, Tennessee place cell production inside the United States, near GM’s assembly footprint. Domestic cell manufacturing has become strategically valuable beyond logistics: it shortens the supply chain, reduces exposure to overseas disruption, and positions the vehicles and the cells they carry to qualify for domestic-content incentives that increasingly shape EV competitiveness. A 10-K that names the towns, not just the partner, is GM signaling that the where of cell production now matters as much as the who.

The contrast with a simple purchase contract is worth making explicit, because it is what the joint-venture structure is really buying. A pure buyer of cells holds a supply agreement: a price, a volume, delivery terms. It owns nothing, controls no roadmap, and stands in line behind the supplier’s other customers when capacity is tight. A co-owner of an “equally owned joint venture” holds a stake in the asset itself — the plant, its output, its profit or loss. That is why GM’s description of the venture as “integral to the operations of our business” is not boilerplate: the cells are not bought at arm’s length, they are produced inside a business GM half-owns and consumes directly. The trade is capital and risk for control and security. GM puts billions into the plants and books its share of their results, and in exchange it is not exposed to a vendor reallocating scarce cells elsewhere.

This is the model much of the industry has converged on: not pure buy, not pure build, but co-own. When you read that an automaker has a “battery joint venture,” the substance is that it has decided the cell is too strategic to outsource entirely — and too hard, and too expensive, to make alone. GM’s filings, with their named plants, named partner, and equity-method accounting, are about as clear a worked example of that decision as the public record offers. The reveal of a new EV is a product story; the line in the 10-K about Ultium Cells Holdings LLC is the business story underneath it.