Other analysts are upbeat about the New York-based company and WisdomTree sees its exponential growth as a positive: "You cannot be a big fund company without big funds," the company said.)

The company also has roughly a quarter of its assets tied to emerging markets and has been hurt as those markets sold off in 2014. Its second-largest fund, the Emerging Markets Equity Income Fund, is down 6.4 percent year to date.

As long as WisdomTree can diversify its assets and attract more investors globally, analysts say, the ETF manager can ride the long-term growth wave of the ETF industry, which has grown from its first U.S. launches in 1993 to $2.4 trillion in global assets and is expected to expand exponentially over the coming years.

WisdomTree is currently the eighth-largest ETF manager globally with some $33 billion in assets. The company has found its niche by focusing exclusively on ETFs, unlike peers such as BlackRock Inc, which says ETFs make up about 21 percent of its total assets under management, and Invesco Ltd, which counts ETFs as about 13 percent of its total assets under management.

WisdomTree also counts among its backers a handful of Wall Street's more well-known individuals. Michael Steinhardt, a legendary investor and hedge fund pioneer, is the company's board chairman and largest shareholder, while Chief Executive Jonathan Steinberg is the husband of business news anchor Maria Bartiromo and son of longtime dealmaker Saul Steinberg.

Their colorful personalities, combined with WisdomTree's unique platform, may make it attractive to larger firms looking to add ETFs to their business.

"It's a digestible acquisition for a lot of asset managers," said Matt Hougan, president of San Francisco-based research and analytics firm ETF.com, noting that WisdomTree's platform "would instantly give them the footprint."

Surinder Thind, a San Francisco-based analyst at Jefferies who covers the company, said that WisdomTree's shares have long traded at a high valuation because of its growth prospects.

It was averaging along the lines of 20 percent organic asset growth each year, Thind said. Now that the company is seeing its inflows turn slightly negative––in part because of a pullback in Japan and emerging markets––some investors may be getting spooked.

Even after recent declines, the company trades at a forward price to earnings ratio of 22.7, still well above the average 16.2 valuation of larger competitors such as BlackRock and Invesco, according to Thomson Reuters data.