$TSLA Tesla Q3 2026: the cash came back, the margins need a footnote, and the big bill is Terafab Tesla's free cash flow is positive again and it cut its 2026 capex guide. On the same call, Musk sized a chip fab project at tens of billions of dollars through early 2028 and more than $100bn over time. This quarter looks cheaper than the next two years will. 1. Margins rebounded, with a footnote GAAP gross margin rose to 19.6% from 16.8% in Q2, and operating margin to 2.6% from 1.4%, still under the 5.8% of a year ago (chart 1). Part of the rebound won't repeat. Energy gross margin jumped to 33.1% from 20.4%, which CFO Vaibhav Taneja put down mainly to tariff refunds and warranty true-downs after a cell vendor agreed to reimburse costs. Automotive margin excluding credits rose to 18.1% from 16.3%, helped by more deliveries in Asia-Pacific. Regulatory credits fell to $113m from $417m a year ago. 2. Cash is positive again, and capex was cut Free cash flow was $1.53bn after negative $1.09bn in Q2, on $6.26bn of operating cash flow and $4.73bn of capex (chart 2). Tesla now guides 2026 capex to about $20bn, down from more than $25bn in July. With $13.0bn spent through Q3, that leaves about $7bn for Q4. It also lined up up to $30bn of borrowing capacity and says it won't draw on it this year. Cash and investments were $45.4bn. 3. Energy: more GWh, less revenue Storage deployed rose 10% to 13.7 GWh, but energy revenue fell 16% to $2.88bn. Revenue per GWh deployed slid from $273m to $210m over the year (chart 3). That's a rough measure, since revenue isn't always booked in the quarter of deployment, but the direction matters. Tesla didn't explain the drop on the call. Musk said Megapacks for 2027 are "almost sold out," and Taneja pointed to better prices ahead as production rises. 4. Autonomy got dates Active FSD subscriptions reached 1.74m, up 67% from a year ago (chart 4). Cybercab has run Robotaxi rides in Austin since Sept 3, and the fleet there is up tenfold since launch. Dallas comes next month, with more cities before year-end, and the first customer-owned cars join the fleet around Q2 2027. Management said Robotaxi revenue becomes "noticeable probably in Q2" next year. These are company targets, and Tesla also said it isn't yet at its 30 cents a mile cost goal. 5. The next big bill is Terafab Musk said Terafab, the chip fab Tesla is building with SpaceX, will take "tens of billions" in equipment through early 2028 and "probably north of 100 billion long term" (chart 5). Who pays what between Tesla and SpaceX isn't settled. The first test chip is due around May or June 2027, with volume production in late 2028. Optimus deliveries to outside companies start around the end of 2027, and Tesla said future capex will keep rising for the Robotaxi fleet, Optimus, compute and the fab. What we'll watch Q4 capex against the roughly $7bn implied by the new guide, whether energy revenue per GWh stops falling, and how Terafab's cost gets split with SpaceX. The $20bn guide covers this year. The Terafab figures are for the years after that.