On April 14, Felipe Villarroel, portfolio management partner at TwentyFour Asset Management, said in a report that after talking with the government bond trading department, TwentyFour could not find a clear answer that led to the sell-off of U.S. Treasury bonds. "The most common reason is the closing of 'basis trade'." He explained that this involves traders having to sell U.S. Treasurys to meet margin calls on leveraged positions. The purpose of leveraged positions is to arbitrage small spreads between U.S. Treasurys and U.S. Treasury futures or interest rate swaps. The huge volume involved triggered a chain reaction, and suddenly many bonds needed a new home, and buyers were too nervous to catch the fall knife in one of the most turbulent weeks in recent times.