BlackRock's spot Bitcoin exchange-traded fund (ETF) experienced a notable surge in inflows on Tuesday, May 21, marking a six-week high for the investment vehicle amidst a rally in the price of Bitcoin.

Preliminary data from Farside Investors revealed that BlackRock’s iShares Bitcoin Trust (IBIT) attracted inflows totaling $290 million on May 21, accounting for a substantial portion of the over $300 million in net inflows into United States spot Bitcoin ETFs. This influx represents a significant uptick compared to the negligible or minimal inflows observed over the past six weeks.

The surge in inflows underscores renewed investor interest in Bitcoin-related investment products, with over $1 billion flowing back into spot Bitcoin ETFs over the past four trading days amid a period of volatility in Bitcoin's price.

Since its launch, BlackRock’s IBIT has amassed a total of $16 billion in inflows, bringing it close to rival Grayscale's Bitcoin Trust (GBTC) ETF, which boasts $20 billion in assets under management (AUM), according to official sources.

Meanwhile, Grayscale's GBTC ETF saw no outflows on May 21, marking five consecutive trading days without net outflows. This recent trend represents a reversal from a four-month period of consistent outflows, with the fund recording inflows of $72.5 million over the past five days.

However, not all Bitcoin ETFs experienced positive flows on May 21. The VanEck Bitcoin Trust ETF witnessed outflows of $5.9 million, while the Bitwise Bitcoin ETF saw $4.2 million in outflows.

In contrast, the Fidelity Wise Origin Bitcoin Fund registered minor inflows of $25.8 million, with other funds maintaining stability.

The heightened enthusiasm for Bitcoin ETFs correlates with a recent uptick in BTC prices, which surged by 12% over the past week. Although BTC briefly reached a six-week high of $71,600 on May 21 before retreating below the $70,000 level, market sentiment remains buoyant.

Additionally, optimism surrounding the potential approval of spot Ether ETFs by the U.S. Securities and Exchange Commission has contributed to the positive momentum in crypto markets since May 20. As investor interest continues to grow, the Bitcoin ETF landscape is poised for further evolution in response to market dynamics and regulatory developments.