Samsung SDI back in profit as AI data center batteries lift it to 3-year high

What happened. Samsung SDI, the South Korean battery maker in the Samsung group, released preliminary third-quarter 2026 results on 29 October. Revenue was 4.69 trillion won, up 52.6% year on year and 20.9% from the second quarter. Operating profit was 407.8 billion won, after a 591.3 billion won loss a year earlier. That is nearly double the second quarter's 203.8 billion won.

Where the money came from. The battery business brought in 4.41 trillion won in revenue (up 55.3%) and 361.9 billion won in operating profit. The company credits sales of energy storage systems (ESS) and battery backup units (BBU) for AI data centers, plus cylindrical batteries for power tools and EVs. Electronic materials for chips and displays added 275.7 billion won in revenue (up 18.9%) and 45.9 billion won in profit (up 18.3%).

What comes next. In the US the company has won more than 60 GWh of ESS orders this year. In October it began mass production of prismatic LFP cells, a cheaper battery chemistry, at its StarPlus Energy plant in the US. In Europe it won an LFP battery project for EVs. It shipped all-solid-state battery samples for humanoid robots. Per Aju Press, the company expects to stay in profit in the fourth quarter.

The catch. Per Yonhap, net profit of 342.2 billion won missed the analysts' average estimate compiled by Yonhap Infomax. Samsung SDI shares traded at 532,000 won on the morning of 29 October, 1.03% below the previous day (Aju Press, 9:09 a.m. Seoul time).

What we don't know. How much of the ESS order book turns into revenue, and when. How long data center demand for storage lasts. This is a summary of the report, not advice to buy or sell.

Confirmed facts

• Samsung SDI Q3 2026 revenue was 4.69 trillion won: up 52.6% from 3.07 trillion a year earlier and 20.9% from 3.88 trillion in Q2.^[1][2]
• Operating profit was 407.8 billion won, against a 591.3 billion won loss a year earlier and 203.8 billion won in Q2; the highest since Q3 2023.^[1][3]
• Battery business: revenue 4.41 trillion won (up 55.3%), operating profit 361.9 billion won, driven by ESS and BBU for AI data centers and cylindrical batteries.^[1]
• Electronic materials: revenue 275.7 billion won (up 18.9%), operating profit 45.9 billion won (up 18.3%).^[1]
• More than 60 GWh of US ESS orders this year; mass production of prismatic LFP cells began in October at the StarPlus Energy plant in the US.^[1]
• Net profit was 342.2 billion won; per Yonhap, below the analysts' average estimate in a Yonhap Infomax survey.^[2]
• At 9:09 a.m. Seoul time on 29 October shares were at 532,000 won, down 1.03%; the company expects to stay profitable in Q4.^[3]

Implications

• ConfirmedAI data center demand for energy storage and backup power is already moving a battery maker's revenue.
• ConfirmedOperating profit jumped, but net profit missed estimates and the market reaction was muted.
• Our readingThe AI boom is spreading from chips to related industries: power, cooling, storage.

Still unknown

• When the US ESS orders turn into revenue.
• The company's 2027 outlook and demand for EV batteries.
• Where the shares close on 29 October.

Who it affects

South Korea, United States, Worldwide. People who follow the AI boom, batteries, EVs and Korean stocks

Sources

1. Samsung SDI (release via Public Technologies, MarketScreener): SAMSUNG SDI Announces Third Quarter 2026 Earnings Results October 29, 2026 · official
2. Yonhap News Agency: Samsung SDI Q3 net income shifts to profit of 342.2 bln won October 29, 2026 · media
3. Aju Press: Samsung SDI Q3 profit hits 3-year high on AI data center demand October 29, 2026 · media