Think sizzling new stock and Alibaba (NYSE:BABA ) pole-vaults to mind.

But ETF investors won’t find that Chinese e-commerce behemoth in most broad-based products. And so they most likely missed out on Alibaba’s 21% gains since its door-busting $25 billion IPO in New York just two months ago.

Broad, mainstream indexes tend to be conservative and are slow to include debuting stocks, said Kathleen Smith, principal of Renaissance Capital, an IPO research and investment management firm.

IPO ETFs aim to fix that sluggishness. Renaissance IPO (ARCA:IPO ) snaps up the largest and most liquid newly listed U.S. companies in as little as five days of initial trading, or upon quarterly review.

A handful of ETFs now have a stake in Alibaba. It’s the top holding in IPO as well as KraneShares CSI China Internet (NASDAQ:KWEB ), with a 12% weighting in each. First Trust U.S. IPO (ARCA:FPX ) allocates 4% to the stock, a top 10 holding.

They’re disruptors of some sort, Smith said about companies in IPO ETFs. They are growing faster than the overall economy.

Investors seem to like that shot at outperforming core, broad-based portfolios with more seasoned stocks. In a year since its launch, IPO has gathered $30 million in assets. FPX seemed to gather dust for its first six years of existence. But since 2013, when Zoetis ‘s (NYSE:ZTS ) debut began a potent string of highflying IPOs, FPX’s assets have ballooned roughly 2,000% to $516 million.

ETFs are an ideal way to capture the returns of securities that aren’t included or are underincluded in core portfolios, experts say.

It’s a diversified, less risky approach than picking the next hot IPO on a stock-by-stock basis, said Ryan Issakainen, an ETF strategist with First Trust Advisors.

High-Profile Names

Although more than half of recent U.S. IPOs are in the red after their first two to four years, their average returns tend to beat the broader stock market. he added. ETFs allow you to get exposure to that average performance, Issakainen said.

So far in 2014, FPX has risen 9% on the strength of Abbvie (NYSE:ABBV ), Facebook (NASDAQ:FB ), HCA Holdings (NYSE:HCA ), Alibaba and Tesla (NASDAQ:TSLA ), which account for 28% of its portfolio combined. That return lags the SPDR S&P 500’s (ARCA:SPY ) 12%. But its three-year average annual 28.39% and five-year average 21.93% beat the S&P 500’s average annual 20.25% and 15.7% for those periods.

The $32 billion Tesla, a terrific performer in the last few years, is not even in the large-cap S&P 500, Issakainen noted. But $30 billion Marsh & McLennan (NYSE:MMC ) is.