U.S. bond mutual funds suffered their biggest weekly redemptions since June as yields reached a two-year high amid speculation that the Federal Reserve will begin cutting back asset purchases.

Bond funds had withdrawals of $11.1 billion in the week ended Aug. 21, the Washington-based Investment Company Institute said.

It was the largest move out of bond funds since the week ended June 26, when $28.2 billion was withdrawn.

The yield on the 10-year Treasury note reached 2.89 percent Aug. 21, the highest since July 2011, according to data compiled by Bloomberg. Rates climbed amid signs that a strengthening U.S. economy could prompt the Fed to scale back its asset-buying program as soon as September. Bonds lose value as rates rise. Investors pulled $7.38 billion from taxable-bond funds the week ended Aug. 21 and $3.77 billion from municipal-bond funds.

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Funds that buy U.S. stocks had net redemptions of $387 million, while those that purchase international equities took in $1.72 billion.