Maybe the only thing harder than getting your hands on hot IPOs at their offering price is figuring out which mutual funds invest in them.

Online screening tools are more likely to turn up a fund manager's height than his or her taste for IPOs, because funds closely guard their portfolio information. This week's Saturday Screen humbly tries to end the mystery -- or at least shed some light on the murky subject -- for mutual fund investors who want a piece of the IPO pie.

Our pals at

Morningstar

sorted all stock funds, looking for those with the highest percentage of assets invested in companies that went public in the last 12 months. As you might imagine, small-cap and tech funds are at the top of the resulting list.

Risky Internet fund

(ATCHX)

Amerindo Technology was way ahead of the pack with more than half of its assets in recent IPOs.

Here are the top 10:

Some names you know, some you don't. But all of these funds focused on smaller and/or technology stocks last year, which served them well. These 10 funds averaged a 164% return in 1999. Amerindo led the pack with a whopping 248.9% return and

(ATEAX)

Atlas Emerging Growth was the only fund not in triple digits, with an oddly humble 42.7% rise.

Atlas Emerging Growth manager Jay Tracey also manages

(OENAX)

Oppenheimer Enterprise, which would've ranked third with nearly 40% of the fund in recent IPOs. Enterprise didn't make the list because it's closed to new investors. Tracey, like many other managers, declined to comment for this story.

PBHG

had three funds in the top 30,

(PBHEX)

PBHG Select Equity,

(PBLDX)

PBHG Limited, and

(PBNOX)

PBHG New Opportunities. The second two are closed to new investors, which kept New Opportunities out of the fifth slot, despite having 35% of its assets in recent IPOs.

Other notable funds in the top 20 are

(TIFQX)

Firsthand Technology Innovators, which is closed to new investors, and

(RSEGX) - Get Report

RS Emerging Growth, run by Morningstar Manager of the Year, Jim Callinan. Both funds have close to 30% of their assets in recent IPOs.

Curious about growth shop

Janus

? The top Janus fund on the list, excluding a small, sub-advised fund, is

(JAVTX) - Get Report

Venture, with 20% of its assets in recent IPOs. The $2.9 billion fund posted a 140% return in 1999.

Ironically, the

(IPOSX)

IPO Plus Aftermarket fund, one of two that specializes in new offerings, didn't crack the top 30. Manager Kathy Smith blames old data. The

Hambrecht & Quist IPO and Emerging Company

fund doesn't make the list because it launched in November and isn't in Morningstar's database yet.

Before you draw too many conclusions from the list, keep in mind that Morningstar data reflect portfolio information from funds' most recent shareholder reports. Some funds' data are fresher than others, and funds that flip IPO shares -- that is, buy at the initial offering and sell soon afterward -- might not have many recent IPOs on their books. Also keep in mind that it's not clear whether the funds on this list bought their shares at the offering price or in the aftermarket.

Nevertheless, it's at least an intriguing first cut. These funds appear to be charting an aggressive course. Past studies have indicated that most IPOs are dicey long-term investments.

But the 1999 performance of these funds is a testament to how much a few hot IPOs can boost a fund's return, particularly a small fund's return. The funds in our screen average $410 million in assets, less than half the size of an average U.S. stock fund.

By comparison, the 10 largest stock funds have, on average, just 0.14% of their assets in recent IPOs. Mammoth funds, like the $100.8 billion

(FMAGX) - Get Report

Fidelity Magellan fund, might get more IPO shares because of their girth, but those shares can't boost returns like they would at a smaller fund.

Of course, there is a risk component to IPO investing -- a point that may be lost on many investors with visions of

VA Linux Systems

(LNUX)

and

Foundry Networks

(FDRY)

dancing through their heads. (The two rose 698% and 525%, respectively, on their first day of trading last year.)

But for every VA Linux, there are IPO bombs like

1-800 Flowers.com

(FLWS) - Get Report

. The company's shares were priced at 21 at their Aug. 3 IPO and closed at 10 3/4 on Thursday. Remember the once-promising

Boston Chicken

? Anyone?

"IPOs are tough now because they're getting younger, newer, and riskier," says Bruce White, a portfolio manager with

Clifford Associates

, a Pasadena, Calif., private money manager. He says his firm rarely participates in IPOs, and when it does, it favors more solid businesses like

UPS

(UPS) - Get Report

, which was the largest U.S. IPO ever when it went public on Nov. 10.

For individual investors, getting a piece of an IPO can be difficult because institutions like funds tend to gobble up all available shares. But it's not impossible, as a recent

Jim Cramer

column points out.

Still, owning IPOs through a mutual fund offers several advantages, not the least of which are professional management and diversification. Both can moderate the IPO market's risk.

But IPOs shouldn't make up more than 5% to 10% of an investor's portfolio, says Bryan Olson, director of research at

Charles Schwab's Center for Investment Research

.

Whether you know it or not, your fund manager might be picking up more IPOs than ever.

(WTSMX)

Westcore Small Cap Growth manager John Karns says many friends and colleagues who run funds at other fund companies and who have never dabbled in the IPO market now feel they "have to" to keep up with peers.

"Fund managers are human. When they see those kinds of big returns they get excited too," says Schwab's Olson.