This trader likely bought their contracts with very high leverage, probably 20x, meaning that they had $20.8 million USD of BTC as collateral for a trade with a

This trader likely bought their contracts with very high leverage, probably 20x, meaning that they had $20.8 million USD of BTC as collateral for a trade with a notational value of 20 times that (416 million). Other platforms with better engineering have software-defined risk limits to prevent people from opening up positions that are too large on high leverage.