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DEEP RESEARCH · SPG

SPG: Precision Reducers and Humanoid Actuators in the Physical AI Era

A review of 3Q25 earnings, the SDD actuator plan, and SPG’s moat in the robotics value chain.

Published: 2025-12-21 · Robotics components/Physical AI · Naver Blog

Investment decisions are your responsibility. This material is research, not a recommendation to buy or sell.

0. Bottom line first

My core read is that SPG is being revalued from a traditional motor maker into a key supplier of robot-joint reducers and integrated SDD actuators. The investment case rests on 3Q25 earnings recovery, the humanoid SDD mass-production plan, and lead-time/price advantages versus Japanese competitors.

Official fact: The source cites 3Q25 consolidated revenue of KRW 115.0 billion, operating profit of KRW 8.5 billion, OPM of 7.4%, revenue growth of 6.5% YoY, operating profit growth of 30.8% YoY, and a 1.4 percentage-point OPM improvement.

Interpretation: I read this as a mix-improvement phase: stable cash flow from standard motors is being supplemented by higher-margin SR and SH precision reducers.

Original image about SPG earnings and business structure

1. Earnings: the structural change behind the numbers

Metric3Q25Source interpretation
RevenueKRW 115.0bn, +6.5% YoYAutomation and robot components offset soft appliance demand
Operating profitKRW 8.5bn, +30.8% YoYHigher-margin product mix
OPM7.4%, +1.4%p YoYReducer yield stabilization and fixed-cost leverage
Export ratioAbout 77% in 2024Favorable KRW/USD helped North American exports
Cash Cow

Standard/geared motors

High-efficiency BLDC demand and long-term customers such as Samsung Electronics, LG Electronics, Whirlpool, and GE reduce volatility.

Growth

SR/SH reducers

Wafer-transfer robots, battery manufacturing lines, and collaborative robots are the growth engines.

Region

North America/Europe

North American revenue grew more than 15% YoY, while Europe is framed as an opportunity through Ukraine reconstruction and defense automation demand.

2. SDD: from parts supplier to solution partner

Official fact: The source says SPG announced on November 20, 2025 that it would enter the SDD actuator business for humanoid robots and target mass production in 1H26.

SDD integrates a reducer, motor, controller, and sensor into one module. The source highlights 90% weight reduction, 2x precision, 1.2x safety factor, efficiency improvement from the 70% range to the 80% range, and more than 50% improvement in noise and lifetime versus Chinese products.

SDD actuatorFrom discrete parts to an integrated drive module
ReducerPrecision torque
MotorDrive force
ControllerMotion control
SensorFeedback
A humanoid joint module that moves SPG up the value chain

Interpretation: Because SPG targets humanoid and robotics ecosystems around Tesla, Boston Dynamics, Samsung, LG, and Hyundai Motor, customer adoption and production validation matter more than the localization theme alone.

3. Moat in the robotics value chain

Original image about SPG reducer and customer moat
  • Technology moat: The source emphasizes that SPG can localize and mass-produce the full reducer lineup: planetary, SH harmonic, and SR cycloid.
  • Production moat: SPG combines high-mix low-volume and low-mix mass production, while internal heat-treatment and machining lines shorten lead times to within four weeks.
  • Price moat: The source cites a 20-30% price advantage versus Japanese competitors such as HDS and Nabtesco.
  • Customer moat: Reducers are hard to redesign once adopted, creating high switching costs and long-term lock-in.

4. Growth path and investment points

The source’s demand logic is that one humanoid robot needs about 40 or more joint modules, creating 6-7x more component demand than a conventional six-axis industrial robot. It also cites Goldman Sachs’ forecast that the global humanoid robot market could reach USD 38 billion, or about KRW 50 trillion, by 2035.

Original image summarizing SPG investment points
  1. Earnings turnaround: 3Q25 operating profit grew 30.8% YoY with margin improvement.
  2. New growth engine: Humanoid SDD actuator mass production is targeted for 1H26.
  3. Economic moat: Full reducer lineup, internal process capability, fast lead time, and price competitiveness.
  4. Macro beneficiary: Smart factories, North American reshoring, and physical AI-driven automation investment.

Sources

Naver original