NEW YORK, Sept 13 (Reuters) - U.S. municipal bond funds reported $820 million of net inflows in the week ended Sept. 12, up from $260 million of inflows during the previous week, according to data released by Lipper on Thursday.
The four-week moving average was positive at $532 million, said Lipper, a unit of Thomson Reuters.
Weekly flows into the funds, popular with retail investors, have been positive since December 2011 with the exception of the week ended April 11.
Net inflows into high-yield funds was $112 million, down from $124 million in the week ended Sept. 5.
Net inflows into exchange-traded municipal funds rose sharply to $59 million from $17.9 million the previous week.
BondDesk Group data for the week ended Sept. 12 showed retail investors bought 2.0 bonds for each one they sold, unchanged from the previous week. The total number of bonds bought was 59,985, while the number of bonds sold was 29,948.
The data is based on odd-lot customer transactions.