BlackRock's spot bitcoin exchange-traded fund (ETF) iShares Bitcoin Trust (IBIT) has outperformed Vanguard's flagship S&P 500 ETF in cumulative returns since its launch in January 2024.

On Sept. 1 (local time), blockchain outlet Bitcoin Magazine reported that Bloomberg senior ETF analyst Eric Balchunas said IBIT's cumulative return slightly exceeded Vanguard's over the comparison period.

Based on Bloomberg tallies, IBIT has risen 71% since inception, while Vanguard's S&P 500 ETF gained 66% in total return. The gap is not large, but the fact that a spot bitcoin ETF has delivered a higher return than a benchmark U.S. stock index product is drawing market attention.

IBIT began trading after the U.S. Securities and Exchange Commission (SEC) approved 11 spot bitcoin ETFs at once in early 2024, after rejecting such products for years. U.S. investors have since been able to choose among various bitcoin-linked products run by Fidelity, Grayscale and Morgan Stanley, among others.

Fund flows are heavily concentrated in BlackRock. By BlackRock's tally, IBIT's assets under management now total $61.4 billion. The No. 2 product, Fidelity's Wise Origin Bitcoin Fund (WBTC), has about $11.0 billion in assets under management.

BlackRock, which has more than $15 trillion in assets under management, drew attention in the crypto market when it applied for a spot bitcoin ETF in 2023. IBIT has become a channel for traditional investors to access bitcoin investment, and its daily trading is relatively active compared with other spot bitcoin ETFs.

Balchunas wrote on social media that IBIT's rise to a 70% return looked like a roller coaster, while Vanguard's VOO followed a relatively gentle path. This is interpreted as meaning that IBIT's price volatility was large along with its high returns.

Recent fund flows have coincided with a rebound in bitcoin's price. From Aug. 17 to 27, investors poured more than $2.8 billion into spot bitcoin ETFs. That is the biggest amount since October 2025, when bitcoin set a new all-time high (ATH). Renewed inflows into ETFs are cited as a factor supporting bitcoin strength by stimulating demand in the spot market.

Bitcoin briefly climbed to as high as $81,281 last week before falling back. It is now around $77,000, down about 1.54% over the past 24 hours. Still, the uptrend over the past two weeks was the strongest in the past three years, and it is up nearly 30% over the past month.

Against this backdrop, the market's focus narrows to two points. One is whether inflows into spot bitcoin ETFs will continue, and the other is whether products such as IBIT can maintain returns and the ability to جذب funds enough to compete with traditional-asset ETFs despite high volatility. So far, BlackRock has remained among the leaders in returns, assets under management and trading volume.

Hard to believe $IBIT is beating $VOO since inception but it's true..altho it's close. And to be fair, IBIT's path to 70% looks like the El Toro roller coaster at Great Adventure (i needed two Advil last time I rode that thing) while $VOO was a walk in the park in comparison.… pic.twitter.com/vpOgI7JZKL