The price surge of Bitcoin on May 21, 2024, was primarily driven by renewed hopes for the approval of U.S.-listed Ether ETFs. Bloomberg analysts raised the approval odds to 75%, which significantly boosted market sentiment. This optimism led to a substantial increase in Bitcoin's price, as it surged over $71,000 early that day, marking its highest point since early April.

Additionally, the surge caused over $260 million in market-wide short liquidations, with Ether shorts losing over $115 million and Bitcoin shorts just over $99 million⁴. The liquidation of short positions often results in a rapid price increase, as it forces the closure of bets against higher price movements.

The market rally began late on May 20 and continued into the next day, following the analysts' raised expectations for the Ether ETF approval. The anticipation of an ETF approval is considered a bullish event because it potentially opens the door to institutional capital, which can lead to higher demand and prices for the associated cryptocurrency.

In summary, the combination of positive news regarding Ether ETFs and the resulting short liquidations contributed to the significant price surge of Bitcoin on May 21.