Municipal bond mutual funds saw a huge week of inflows, as investors continue to see strength in the market.

Muni bond funds saw $901 million of inflows from funds that report their flows weekly for the week ended May 9, according to Lipper FMI.

The numbers more than doubled those from last week. There were net inflows of $447 million the previous week, which ended May 2. The market has now seen positive flows for 33 out of the past 36 weeks.

Demand for intermediate- and long-term munis set the pace for the market, with 10-year and 30-year triple-A yields each falling six basis points since last Friday, according to Municipal Market Data numbers.

In addition, demand for long-term bond funds remained robust, more than doubling flows recorded the previous week. Long-term muni funds that report their flows weekly rose $498 million.

Intermediate muni bond funds more than doubled their reported inflows. Those funds that report their flows weekly saw inflows of $173 million, against $75 million the previous week.

This week, assets for all funds that report their flows weekly rose to $296.7 billion from $294.5 billion the previous week.

The value of the holdings for weekly reporting funds rocketed by $1.45 billion. The week before, they jumped by $1.11 billion.

The four-week moving average for all municipal bond mutual funds that report their flows weekly experienced a $491 million inflow, up from a $252 million gain the week before.

High-yield muni funds also recorded a strong week. They have seen inflows for 21 of the previous 22 weeks.

Funds that report weekly saw $258 million in inflows, Lipper said. The previous week, high-yield funds reported $160.1 million in inflows.

Assets for high-yield funds that report their flows weekly rose to $39.63 billion, up slightly from $39.10 billion the previous week.

The value of the holdings for weekly reporting funds increased by $268 million. Last week, they rose by almost $299 million.

The four-week moving average for all high-yield muni bond funds that report their flows weekly was a $186 million inflow, up from a $151 million inflow the week before.