## Mercuria Trader Sonny McNess Exits After Building Massive LME Aluminum Bets That Forced Rule Changes
A key architect of the enormous aluminum positions that forced the London Metal Exchange (LME) to rewrite its rulebook has departed the firm. Sonny McNess, a veteran trader at Swiss commodity giant Mercuria Energy Group, has left the trading house. His exit follows a period of intense scrutiny after the positions he helped build grew so large they threatened to distort the market's fundamental pricing mechanisms.

The scale of the aluminum bets, concentrated in a single dominant position, became so significant that the LME was compelled to intervene. The exchange implemented special lending rules, a rare measure designed to alleviate a squeeze and improve metal availability for other market participants. This direct regulatory response underscores the exceptional nature of the trading activity orchestrated from within Mercuria.

The departure signals a potential recalibration at Mercuria following the high-profile episode. While the immediate market squeeze has been addressed by the LME's actions, the incident highlights the ongoing tension between aggressive proprietary trading strategies and exchange oversight. It raises questions about internal risk controls at major trading houses and their ability to manage positions of a size that can trigger systemic rule changes.
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- **Source**: Bloomberg Markets
- **Sector**: The Vault
- **Tags**: commodities, LME, aluminum, trading, regulation
- **Credibility**: unverified
- **Published**: 2026-04-09 18:57:14
- **ID**: 57454
- **URL**: https://whisperx.ai/en/intel/57454