Vanguard VOO's hidden $40B trade affects your retirement fund

A $40 billion institutional trade cycles through Vanguard's S&P 500 exchange-traded fund (VOO) every quarter, affecting retirement account holdings, Bloomberg reported .

Foreign institutions are behind the quarterly movement, exploiting a scheduling gap between VOO and BlackRock's iShares Core S&P 500 ETF (IVV) to sidestep U.S. dividend taxes.

The two funds track the same index and charge the same 0.03% annual fee, but they distribute dividends on different dates each quarter, Bloomberg confirmed.

That scheduling gap lets overseas investors sidestep the 30% United States withholding tax on dividend income from both funds.

The strategy probably saved foreign investors an estimated $147 million in U.S. taxes last year, and the next rotation is expected around Sept. 15, 2026, according to Bloomberg calculations.

The trade is legal, but the friction costs fall on domestic shareholders who hold VOO or IVV through each quarterly rotation cycle.

How staggered dividend dates on VOO and IVV enable a tax-free rotation

VOO and IVV hold the same 500 large-cap stocks, giving a dollar in one fund the same economic exposure as a dollar in the other, Bloomberg reported.

The key difference is timing: IVV's third-quarter ex-dividend date falls on Sept. 15, 2026, and VOO's arrives about two weeks later, near the end of the month, according to BlackRock's 2026 distribution schedule .

Under the Internal Revenue Code , foreign investors owe a 30% withholding tax on U.S.-source dividend income, though tax treaties reduce the effective rate to 15% or lower for many institutional holders. The rotation avoids the levy entirely, regardless of treaty rate.

Foreign institutions exit IVV before its ex-dividend date, move the capital into VOO, then reverse course before VOO pays its own quarterly distribution.

Share prices typically fall by the dividend amount on the ex-dividend date, so selling beforehand converts the payout into untaxed capital gains.

That process provides overseas investors with continuous S&P 500 exposure, with no taxable dividend income and no withholding liability on distributions from either fund.

Museum Mile Funds CEO Mayank Mohan told Bloomberg that the strategy became viable only after multiple large, low-fee S&P 500 ETFs existed for institutions to rotate among.

With the emergence of IVV and VOO you have the availability of doing these switching trades .

The flow pattern first became visible in fund flows in 2023 and has grown in dollar volume since, Bloomberg's investigation documented .