Many market participants may be on vacation, but there's still interest in municipal bond mutual funds. Flows to muni bond funds rose on the week, keeping their hot streak alive.

Those funds that report their flows weekly saw $613 million of inflows for the week ended Aug. 29, according to Lipper FMI. They have seen inflows for 20 consecutive weeks.

There were net inflows of $436 million in the week ended Aug. 22. For context, there have now been inflows to muni bond funds for 49 of the past 52 weeks.

Muni yields recorded their second straight week of falling yields, albeit modestly and moving in tandem with those of Treasuries. Yields since last Friday fell several basis points from the belly of the curve on out.

Muni ratios to Treasuries mostly hovered on the week. They held at percentages of at least 105%.

And although slight, the week's primary issuance saw decent reception, as muni bond investor appetite remained robust.

Assets for all muni funds that report their flows weekly climbed to $311.8 billion from just under $310 billion the week before.

The value of the holdings for weekly reporting funds jumped by almost $1.2 billion. The week before, they increased by just $64.5 million.

The four-week moving average for all municipal bond mutual funds that report their flows weekly saw a $788 million inflow, rising slightly from a $761 million gain the week before.

Long-term bond funds kept their modest streak of inflows going. But their share of overall inflows slipped below half of the total for muni bond funds.

Long-term bond funds that report their flows weekly saw inflows to the tune of $240 million, halving from $282 million the week before.

High-yield muni funds also saw inflows, though they dropped for the third consecutive week. Flows have been positive for 23 consecutive weeks, and 37 of the previous 38 weeks.

High-yield funds that report weekly saw $134 million in inflows, Lipper said. The previous week, they reported $186 million in inflows.

Assets for high-yield funds that report their flows weekly increased to $43.86 billion, up from $43.52 billion the previous week.

The value of the holdings for weekly reporting funds rose by $206 million. Last week, they were almost unchanged from the previous week; they decreased by just $26,000.

The four-week moving average for all high-yield municipal bond funds that report their flows weekly was $213 million of inflows, inching up from $212 million the week before.