(Bloomberg) -- Investors are pouring a record amount of money into exchange-traded funds that focus on municipal debt even as the consensus on Wall Street calls for higher interest rates in coming months.

Individuals this year have added about $1 billion to ETFs that purchase state and local bonds, the fastest annual start since the funds started in 2007, according to data compiled by Bloomberg. The investment tools, which typically track indexes and can be bought and sold during the trading day, have taken on a growing role for muni investors, almost doubling in assets since 2010.

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