Vanguard’s blue-chip US stock exchange-traded fund has become the world’s biggest, seizing the crown from State Street’s S&P 500 tracker, in a sign of how a race to slash fees is reshaping the industry.

The Vanguard S&P 500 ETF VOO has dethroned State Street's SPDR S&P 500 ETF SPY as the largest ETF in the world. VOO now boasts approximately $632 billion in assets, according to Bloomberg data, surpassing SPY’s $630 billion.