Construction Aluminum Rallies as Automotive Gets Shorted—COT Report Reveals the Split

The U.S. Commodity Futures Trading Commission's (CFTC) latest Commitments of Traders (COT) report for aluminum in December 2025 reveals a striking divergence in speculative positioning between construction-linked and automotive-grade aluminum markets. This split—1,054 net long contracts in construction aluminum versus a record -2,900 net short contracts in automotive-grade aluminum—highlights a capital reallocation that investors cannot ignore. The data underscores a macroeconomic shift: infrastructure-driven demand is outpacing automotive resilience, creating asymmetric risks and opportunities across industrial sectors.

Construction Aluminum: A Policy-Driven Bull Case

The Aluminium Midwest Premium (MWP) futures contract (Code 191693), a proxy for construction-linked aluminum, holds a speculative net long of 1,054 contracts. This position is overwhelmingly driven by commercial hedgers (84.1% of longs), reflecting structural supply constraints and policy tailwinds. U.S. Section 232 tariffs, Chinese production caps, and the One Big Beautiful Bill Act (OBBBA)—which allocates $1.2 trillion for infrastructure—have created a perfect storm of demand and scarcity.

The MWP price of $1,323 per metric ton (MT) aligns with historical trends where policy-driven demand outpaces supply. For investors, this signals a strong case for construction materials equities. Firms like Kaiser Aluminum (KALU) and Vulcan Materials (VLC) have leveraged their pricing power to pass on rising input costs, with EBITDA margins expanding by 8–12% in 2025. The COT data suggests these trends will persist, with infrastructure spending acting as a buffer against broader economic headwinds.

Automotive Aluminum: A Margin Compression Warning

In stark contrast, the Aluminium Euro Prem Duty-Paid (Code 191696) contract, representing automotive-grade aluminum, is net short by -2,900 contracts—a record low. Non-commercial short positions surged by 1,490 contracts in Q4 2025, exposing automakers to un-hedged costs. Tesla (TSLA) exemplifies this vulnerability: its EBITDA margins fell from 14% in 2023 to 6% in Q2 2025, directly tied to aluminum inflation and weak demand. Unlike construction firms, automakers lack pricing power to offset rising input costs in a softening market.

The speculative net short in automotive aluminum acts as a leading indicator of margin compression. With aluminum prices at multi-year highs and automakers struggling to pass on costs, the sector faces a perfect storm of declining profitability. This is not a temporary blip but a structural shift driven by capital reallocating away from cost-sensitive industries.

Strategic Implications for Investors

The CFTC's positioning data serves as a sector rotation barometer. For investors, the message is clear: overweight construction materials and underweight unhedged automotive stocks. The -2,900 net short in automotive-grade aluminum is a red flag for automakers like Tesla, while the 1,054 net long in construction aluminum validates the resilience of firms like KALU and VLC.

Actionable Steps:
1. Long Construction Materials Equities: Position in companies with pricing power and infrastructure-driven demand, such as KALU and VLC.
2. Short or Avoid Unhedged Automakers: Tesla and peers with weak EBITDA trends face margin compression risks.
3. Monitor COT Reports Weekly: The CFTC's Friday releases (e.g., December 12 and 19) will provide real-time updates on speculative positioning shifts.

The COT report is not just a data point—it is a roadmap for navigating macroeconomic tailwinds and headwinds. As speculative capital flows toward sectors with structural demand and pricing power, investors must align their portfolios accordingly. The aluminum market's split positioning is a harbinger of broader industrial trends, offering a rare opportunity to capitalize on sector-specific imbalances.