market volatility supercharged the growth of municipalbond exchange traded funds in 2022 at the expense of openend mutual funds which may lose some of those assets for good despite the worst market rout in 40 years investors plowed a record 278 billion into municipalbond etfs this year a striking contrast to openend funds which lost more than 130 billion as much as half the inflows came from mutual fund holders selling shares at a loss to offset gains and swapping into etfs according to estimates by drew pettit director of etf analysis and strategy at citigroup inc