CATL vs BYD — one sells batteries to everyone, the other builds everything in-house. Who wins?

I've spent a lot of time looking at the EV supply chain and it's kind of wild how little attention CATL and BYD get from Western investors given that they together control 55% of the global battery market. So here's a comparison of both because they have totally different business models and the difference matters if you're thinking about investing in either. CATL is the world's largest battery maker. 37.9% global share, been #1 for eight years straight. They supply basically everyone: Tesla (biggest customer), BMW (4 billion euro supply deal), Mercedes, VW, Stellantis, Ford, Honda, Hyundai, and every Chinese EV brand you can think of. 17 million cars on the road running CATL cells. 2024 revenue was RMB 362B (\~$52B), down \~10% because lithium prices crashed and selling prices dropped 25%. But here's the thing - net profit went UP 15% to \~$7B because their margins actually expanded as lithium got cheaper. Q3 gross margin hit 31%, which is crazy for a battery company. They have 300B+ RMB in cash. 646 GWh of production capacity across 15 plants. They're expanding into Hungary, Germany, and licensing tech to Ford in the US. BYD went a completely different route. They don't just make batteries - they make the batteries, the cars, the motors, the power electronics, and increasingly their own chips through BYD Semiconductor. In 2025 they passed Tesla as the world's biggest EV maker by volume. The origin story is worth knowing: Wang Chuanfu started making rechargeable batteries in 1995, bought a failing state car company in 2003, and Buffett's Berkshire invested $230M for 10% in 2008. Their Blade Battery (LFP chemistry) was a game changer - that viral video where they puncture the cell and it doesn't catch fire basically proved LFP could compete with nickel batteries on performance while being cheaper and safer. The vertical integration is deep. BYD controls costs at every level of the stack. When your competitor has to buy batteries from a supplier, negotiate margins, deal with delivery schedules - and you just make it all yourself - you can move a lot faster and cheaper. Here's how they stack up: |CATL|BYD| |:-|:-| |2024 Revenue|\~$52B| |Battery market share|37.9%| |Model|Sells to everyone| |Gross margin|24.4%| |Main edge|Scale + customer diversification| If I had to pick one: I lean CATL. The supplier model has a wider moat. If Tesla leaves BYD (they won't buy from a competitor), CATL still has 20+ other customers. BYD's integration is powerful but it also means every automaker sees them as a competitor, which limits their third-party battery sales. CATL's risk is that batteries become commodities and margins compress. That's why they're pushing sodium-ion and condensed matter batteries - staying ahead on tech is how they keep pricing power. BYD's risk is that they're trying to do too many things at once. Cars, batteries, chips, software, global expansion into Europe and Southeast Asia with local factories. It's worked so far but the execution gets harder as they scale internationally. The big risk for both: geopolitics. 100% US tariffs on Chinese EVs, potential restrictions on battery components, and the general China risk discount that Western investors apply. If US-China relations deteriorate further, both stocks get hit regardless of fundamentals. China's domestic market is also a bloodbath. 100+ EV brands fighting over the same customers with razor margins. Even CATL and BYD feel this. Battery demand is projected to go from \~1,000 GWh to 2,500+ GWh by 2030 so there's probably room for both to win. But if you're a Western investor, the geopolitical risk is real and you need to be comfortable with it.