Group 1 - The core lesson from historical financial collapses is the importance of position control, with excessive leverage being a primary cause of fund failures [2][5][10] - Long-Term Capital Management (LTCM) utilized a strategy of convergence trading, but their extreme leverage of 32:1 led to their downfall when market volatility increased [2][5] - Victor Niederhoffer's experience in 1997 illustrates similar issues, where aggressive options selling resulted in significant losses due to market downturns and forced liquidation [6][7][10] Group 2 - The 2018 "volatility apocalypse" demonstrated that even professional traders can repeat the same mistakes regarding position control and leverage [11][13] - The case of Archegos Capital Management highlights the dangers of high leverage, resulting in a $20 billion loss in a week due to margin calls [15][18] - Greed and arrogance are identified as root causes for traders taking on excessive positions, aiming for unrealistic returns by leveraging strategies beyond their means [18][22] Group 3 - Effective risk management requires traders to assume extreme price movements can occur at any time, rather than relying solely on historical data [19][22][25] - Strategies with negative skewness, which often yield small gains but can incur large losses, necessitate rigorous stress testing to determine appropriate position sizes [25] - The importance of establishing robust risk management assumptions is emphasized, as failure to do so can lead to catastrophic losses, akin to the "turkey graveyard" concept described by Nassim Taleb [25]