There's a lot of buzz about actively-managed ETFs, but it will take a while for the trend to catch on.

By one count, there are 37 actively-managed exchange-traded funds. By another count, there are only 16. If anything, the discrepancy points to the still muddled world of actively-managed ETFs.

Pacific Investment Management Company's plan to roll out a Total Return ETF later this year that mimics its popular Total Return mutual fund could put some juice into the sector. But for now, active ETFs remains a trend that still hasn't caught on with the investing public.

According to Morningstar, there are 37 active ETFs with total assets of $5.8 billion. That's the proverbial drop in the bucket within the entire ETF universe of roughly 1,200 funds and more than $1 trillion in assets. But some analysts expect the number of actively-managed ETFs to grow, particularly as traditional investment managers look to enter the space.

"We think 2011 will be the year of the active ETF launch, not necessarily the year of active ETF assets being gathered," says Morningstar ETF analyst Robert Goldsborough. "But we'll probably see it [more inflows into active ETFs] in coming years."

Goldsborough notes that institutional investors currently are deterred by the lack of a three-year track record at active ETFs, while retail investors are still going through a learning curve with these products.

So far, the leading players in the actively-managed ETF space include AdvisorShares, Columbia Management Investment Advisers, Pimco, Wisdom Tree and PowerShares.

Tom Graves, an equity analyst with Standard & Poor's, believes actively-managed ETFs might catch on quicker in non-equity asset classes. "I think there's more opportunity to attract ETF investors in the fixed income and currency categories because there's less competition than in equities," he says.

Jeff Tjornehoj, a research manager at Lipper, counts only 16 actively-managed ETFs. He says that's because he has a stricter definition for what comprises "actively-managed."

"My concern is that we're just getting reconstructed indexes and calling that active," he says. "If components of your fund are there only because the algorithm behind your index put them there and that's what you're trying to track, to me it's just an index fund with faster reconstitution.