On June 2, 2026 Vanguard S&P 500 ETF (VOO), the largest ETF in the world, passed the milestone of $1.0trn in assets under management. After the ETF passed the $1.0 trn milestone earlier in the month, VOO faced outflows and could not reach the $1,000.00 bn in AUM at the end of June. Nevertheless, VOO has manifested a new reality in which ETFs can become larger than $1.0 trn in assets under management. Reaching this milestone for a single ETF is quite impressive, even as the overall size of the U.S. ETF industry may lead to the assumption that it might be normal that ETFs have such high assets under management. It is also impressive to see at which speed VOO reached this milestone as the ETF roughly doubled its assets under management from $508.7 bn at the end of August 2024 to $979.0 bn at the end of June 2026. Hence, it took the Vanguard S&P 500 ETF (VOO), only 22 months, or 669 days, to gain another $470.2 bn in AUM, after it took 15 years and nine months to gather the first $500.0 bn in AUM. This means the Vanguard S&P 500 ETF grew on average by $702.9 mn per day between August 31, 2024, and June 30, 2026.
Graph 1: Assets Under Management of the Three Largest ETFs Globally, January 31, 2016 – June 30, 2026 (in USD)
Source: LSEG Lipper
That said, there are four ETFs (Vanguard 500 Index Fund; ETF, iShares Core S&P 500 ETF (AUM: $888.1 bn), State Street SPDR S&P 500 ETF Trust (AUM: $781.2 bn), and Vanguard Total Stock Market Index Fund; ETF (AUM: $663.5 bn)) globally which hold more than $500 bn in assets under management, but none of them are currently close to VOO in terms of assets under management. All of these four ETFs are domiciled in the U.S. As one can see from the ETF names, the largest three ETFs in the world are investing in the S&P 500 Index, while the fourth is investing in the overall U.S. stock market, which shows that U.S. investors seem to have a home bias when it comes to their ETF investments.
A Brief History of the Vanguard S&P 500 ETF (VOO)
The foundation of the Vanguard S&P 500 ETF is the Vanguard 500 Index Fund, which was launched on August 31, 1976, by John Bogle. This fund was the first index mutual fund for retail investors which tracked the S&P 500. The Vanguard S&P 500 ETF was launched on September 7, 2010, roughly 34 years after the original mutual fund, as a share class of the Vanguard 500 Index Fund and not a standalone portfolio.
The dual share class model was a patent that Vanguard held from April 2005 until May 2023. Actually, the first patent filling was made in March 2001, after the SEC granted the first exemptive relief to Vanguard allowing its index mutual funds to offer ETF shares as an additional share class of the same fund in October 2000. During this period Vanguard was the only fund/ETF promoter who was able to offer a dual share class model.
In more detail, the relief was not a single blanket rule but a series of exemptive orders (the so-called “Vanguard Orders”) issued starting in 2000 under the Investment Company Act of 1940. These orders allowed a single open-end fund portfolio to issue both: traditional mutual fund share classes and exchange-traded share classes. This means that all share classes (mutual funds and the ETFs) share the same portfolio. As a result of this structure investors got the advantage that they can convert mutual fund shares into ETF shares, et vice versa, within the same portfolio tax free. This has become one of the key structural features distinguishing Vanguard ETFs.
Share Class Overview of the Vanguard 500 Index Fund
As the Vanguard S&P 500 ETF is not a standalone portfolio it is of interest to look at the other share classes to evaluate the overall assets under management managed within the same portfolio. Actually, the Lipper database shows that there are currently three mutual funds and one ETF linked to the same portfolio. The mutual funds are the Vanguard 500 Index Funds; Admiral (AUM $680.5 bn), the Vanguard 500 Index Fund; Institutional (AUM $12.8 bn), and the Vanguard 500 Index Fund; Investor (AUM $2.8 bn), while the Vanguard S&P 500 ETF is the only ETF in this array.
Summing the assets under management in all share classes up brings the total assets under management within the portfolio of the Vanguard 500 Index Funds up to $1,675.0 bn. By looking at this total one needs to bear in mind that Vanguard is managing additional portfolios in the U.S. and globally which do also offer exposure to the S&P 500. This means that Vanguard is one of the largest owners of the companies which are included in the S&P 500.
All values are in US dollar, as of June 30,2026
This article is for information purposes only and does not constitute any investment advice.
The views expressed are the views of the author, not necessarily those of Lipper or LSEG.
