Taxable bond funds and exchange traded funds (ETFs) enjoyed another banner month in April, according to Morningstar's latest Direct Fund Flow Update, adding another $17.7 billion and $23.3 billion in inflows, respectively.

For the month, taxable bond funds recorded the largest percentage increase of any asset class while inflows for U.S. ETFs more than tripled from the $6.9 billion added in March.

Meanwhile, long-term mutual funds posted inflows of $23.9 billion, down from $27 billion in March and municipal bond funds took a step back with redemptions of just over $3.8 billion.

The report also found that inflows to bank-loan funds declined for the third month in a row to $3.4 billion and inflation-protected bond funds garnered $1.2 billion in fresh money, more than they'd received in any month over the past year. 

U.S. stock funds added another $2.1 billion in April, a significant jump from the $1 billion in outflows they endured in March as investors continue to jump aboard this fairly sustained bull run.

Small-cap and mid-cap stock funds recorded combined inflows of $3.4 billion last month but their large-cap brethren weren't as fortunate. Large-growth and large-value funds shed a combined $2.7 billion with large-value fund Fairholme losing almost $1 billion itself -- nearly threefold more than the fund's previous low-water monthly outflow in March 2009.

"Granted, the fund is down more than 4% so far this year, and it trails the S&P 500 index by nearly 13 percentage points, but these outflows are far worse than anything the fund experienced even during the 2008-09 bear market," the report said. "Notably, the fund had a surge of nearly $1.2 billion in combined inflows in January and February. It's tempting to wonder whether some of this new money has already headed for the exits."

International stock funds, which have added more than $93.5 billion in the past year, pulled in another $2.9 billion in April. Meanwhile, U.S. stock funds reported outflows of more than $56.2 billion between April 2010 and last month.

U.S. stock ETFs, which have become increasingly popular with both retail and institutional investors of late, stormed back from outflows of $3.3 billion in March to garner another $10.2 billion in inflows last month.

International ETFs continued their recent strong momentum, too, adding $7.1 billion in April after picking up $6.7 billion in March.

Commodities ETFs tacked on another $821 million in inflows after losing $218 million in March, with most of last month's inflows tied to physically-backed gold funds, Morningstar said.

Not to be outdone, taxable-bond ETFs raked in another $3.6 billion last month and municipal-bond ETFs recorded inflows of $98 million -- their strongest month since October.