> ## Documentation Index > Fetch the complete documentation index at: https://www.questforedge.io/llms.txt > Use this file to discover all available pages before exploring further. # Einar Aas and the Nordic Power Market Collapse #### What Happened In 2018, Norwegian trader Einar Aas suffered losses exceeding €100 million while trading energy derivatives in the Nordic power market. The losses were large enough to trigger a default at Nasdaq Clearing, impacting multiple market participants. *** ### Market Context Aas was trading **power spread contracts**, which are price differences between regions in the electricity market. These spreads are typically: * low volatility * mean-reverting * considered relatively stable This made them attractive for leveraged positions. *** ### The Core Mechanism The strategy relied on: * historical stability of spreads * convergence between regional prices * relatively small price fluctuations However, these assumptions failed under changing market conditions. *** ### What Changed An unusual combination of factors occurred: * weather-driven supply shifts * changes in energy flows across regions * reduced liquidity This caused spreads to move sharply and persistently. ***
### Why It Failed #### 1. Concentration Risk Multiple positions were exposed to the same underlying factor: → regional price relationships in the power market Despite appearing diversified, the portfolio was highly concentrated. *** #### 2. Correlation Breakdown Assets that historically behaved predictably diverged. → relationships that were assumed stable stopped holding *** #### 3. Leverage Positions were large relative to capital. → small price changes produced outsized losses *** #### 4. Tail Risk The strategy worked under normal conditions. → but was exposed to rare, high-impact events *** ### Outcome Losses accumulated rapidly. Margin requirements increased. Positions could not be maintained. → The account collapsed. *** ### Key Insight > Stability in historical data does not guarantee stability under stress. *** ### Structural Lesson The failure was not due to a single bad trade. It resulted from: * concentrated exposure * reliance on stable correlations * sensitivity to rare events *** ### Connection to Risk Management This case illustrates that: * low volatility strategies can carry hidden risk * correlation can increase suddenly * diversification can be misleading *** ### Final Insight The critical question is not: > “How stable has this strategy been?” But: > “What happens when its underlying assumptions break?” *** ### Related Concepts → *Accounting for Correlated Risk in Trading*\ → *How Losing Streaks Actually Behave*\ → *The Real Reason Accounts Blow Up*