The Actuator Oligopoly's Endgame

When Tesla builds its own motors, China prices them at cost, and the old guard has nowhere left to hide.

By Oscar D

In 1999, two Japanese companies — Harmonic Drive Systems and Nabtesco — made a quiet agreement. Harmonic Drive would focus on smaller, high-precision harmonic reducers for the wrist joints and elbows of industrial robots. Nabtesco would focus on larger, high-torque RV reducers for the shoulders and hips. Together, they divided the global precision reducer market between them, a gentleman’s arrangement that held for nearly two decades. If you wanted to build a robot that moved precisely, you bought from one of these two companies. End of story.

That agreement was dissolved in 2022. Nabtesco sold its approximately 19% stake in Harmonic Drive Systems by early 2025, netting roughly $357 million in the process. The two companies, which had been cross-shareholders and strategic partners since 2005, are now independent competitors in a market that’s about to get dramatically bigger — and dramatically more competitive. I think that timing tells you everything you need to know about where this industry is heading.

So today I want to talk about the endgame. Over the past week, we’ve traced the actuator supply chain from its origins in a 1955 patent by C. Walton Musser, through forty years of Japanese manufacturing dominance, to the Chinese disruption that’s now remaking the competitive landscape. Amanda J mapped the bottleneck in Part 1. I traced the technology arc from harmonic drives to torque motors in Part 2. Phil D showed us the Chinese market share surge in Part 3 and the procurement wars between Tesla, Figure, and Unitree in Part 4. Now I want to synthesize all of that into a single question: who wins, who loses, and what do you do about it?

I think the answer has three parts. But before I get to the investment thesis, let’s be precise about what we’re actually looking at — because the numbers matter, and in my experience, most of the market commentary on the actuator supply chain is about five years behind the data.

This matters because the precision reducer oligopoly isn’t one company controlling 85% of the market, as some earlier analyses suggested. It’s more nuanced — and in some ways, more interesting. What we actually have is a market dominated by roughly five players, with the top two (HDSI and Nabtesco) holding a combined ~60% share of the high-end precision reducer market for robotics applications, and a third Japanese player (Nidec-Shimpo) adding another ~12%. The Chinese challengers — Green Harmonic, Leaderdrive, Laifual, and a dozen smaller players — have collectively grown from under 10% in 2020 to somewhere around 30% today.

Figure 1: Estimated precision reducer market share in robotics applications, early 2026. Japanese incumbents still hold roughly 70% combined, but the direction of travel is clear. Source: Machine Narrative Research estimates.

HDSI is the clear leader in harmonic drives specifically — the smaller, higher-precision reducers used in robot wrists, elbows, and increasingly, humanoid hand joints. I’d estimate their share of the high-end harmonic drive market at roughly 60%, though exact numbers are hard to come by since the market isn’t tracked by any single authoritative source. Nabtesco dominates RV reducers — the larger, higher-torque gearboxes for shoulder and hip joints. The distinction matters because the humanoid robot buildout is likely to require both types: harmonic drives for the dozens of small joints in the hands and wrists, RV reducers for the larger load-bearing joints in the arms and legs.

The Rare Earth Trap

Let me pause here and talk about something that I think gets lost in most supply chain analyses, because it sits one layer deeper than the gearboxes and the torque motors. Every precision actuator — whether it uses a harmonic drive, a planetary gear, or a direct-drive torque motor — depends on permanent magnets. Specifically, neodymium-iron-boron (NdFeB) magnets, the most powerful commercially available permanent magnets in the world. And China controls roughly 90% of the global supply chain for NdFeB magnet manufacturing.