Fund investors are plowing money into tech funds in

record amounts these days, so plenty of folks will feel it when this market-leading sector cools -- or at least takes a cigarette break.

What's that you say? You've only got a small piece of your portfolio in the sector? Check again. In order to stay competitive, the average stock fund manager has steadily raised his or her fund's tech allocation from just 2.6% in 1991 to 24.3% last year, according to

Morningstar

.

Translation: The fund you bought three or more years ago might be a bit -- or quite a bit -- more tech-heavy now. That's not necessarily a bad thing, as long as you're aware of it. Otherwise you could be more exposed to tech than you'd like.

So, this week's Saturday Screen looks for U.S. stock funds that have upped their tech allocations the most over the past three years on a percentage basis. We screened out closed funds, tech funds, funds with less than $100 million and funds with managers who've been in place for less than five years. Here's our list of 20.

As you might imagine, raising the tech weighting has helped these funds along. On average over the past year, they're up 30.8%, beating the

S&P 500

index by more than 20 percentage points. In general, the bigger the tech weighting, the better the performance.

Many of these funds' managers probably felt they had to raise their tech weighting simply because the sector has left others in its dust. Also, since the sector's appreciation has made it a bigger chunk of the S&P 500 index -- a widely accepted official and unofficial benchmark -- funds needed to stock up on tech to compete.

Not all of the allocation increases are earth-shattering. Let's thin the list, starting at the top.

The $218 million

AIM

(GPSAX)

Global Consumer Products & Services is a bit of an oddball. It's a thematic fund that, as you might imagine, invests in companies that make, market or sell products and services to consumers around the world. Morningstar labels it a large-cap growth fund, and

Lipper

puts it in the specialty/miscellaneous pile. Though the increase in its tech holdings looks large on a percentage basis, on an absolute basis, its holdings are relatively small.

You also might not worry too much about value and equity-income funds whose tech allocations are still below the S&P 500's weighting, which was 28% as of Jan. 31. That includes

(MUHLX) - Get Report

Muhlenkamp,

Lord Abbett

(LAVLX) - Get Report

Mid-Cap Value and

HighMark

(HMIEX)

Income Equity and

John Hancock

(TAGRX) - Get Report

Large Cap Value.

Yes, these funds are designed to be conservative and valuation-conscious, so some investors might blanch at their sizable increases in technology. But these funds are still underweighted in a sector where many stocks are pricey and volatile.

AIM

(AVLFX)

Value's tech stake has shot up and the fund is slightly overweighted in tech, according to its most recent shareholder report filed at the end of October. That said, the fund's average price-to-earnings ratio is below that of the S&P 500, so it's not taking risks elsewhere.

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Same goes for

Fidelity

fund's nearly fivefold jump in tech weighting from 6.5% in 1997. The fund's current weighting isn't that heavy compared to the S&P 500, and the fund's average price-to-earnings ratio is right at the index's average.

Maybe the investors who should pay the most attention to the list are those who own shares of

Strong

and

Janus

funds. Why? Because Strong has three funds on the list and Janus would've had three if

(JAVLX)

Twenty and

(JAVTX) - Get Report

Venture weren't closed to new investors. This shows a broader, firm-specific, rather than fund-specific, move to the sector.

"The reality is

tech's the only thing that's working and that's where you've got to be," says Ian Rogers, co-manager of Strong

(STRFX)

Total Return.

Clearly he's not the only one at the Milwaukee-based fund shop who thinks so. While

(SEQIX)

Equity Income's rising stake is still below-market,

(SGRIX)

Growth & Income has risen from just over 6% to more than 38%. Both funds are run by Rima Milaitis.

A fourth Strong fund,

(STDIX)

Discovery, didn't make our list, but managers Richard Strong and Charles Paquelet had just over 9% in tech in 1997 and now have more than 38%. The firm also launched its first two tech funds at year-end:

Strong Internet

and

Strong Technology 100

.

Nearly everyone knows Janus managers tend to take

big bets on many of the same tech stocks, but it's interesting to look at the numbers. As you can see,

(JAENX) - Get Report

Enterprise's 20-fold jump is pretty impressive. But Venture and Twenty are worth noting too. Both would've been on our list if they weren't closed. Each had around 10% of their assets in tech back in 1997. Today, both funds have more than half of their assets riding on the sector.

Obviously, it's hard to fault managers for ramping up their exposure to a market-leading sector. But you should know it if you're four or five times more exposed to a pricey, volatile industry than you were in the past. That way, you won't unwittingly raise your allocation further with other investments.

Strong's Rogers says focusing on tech stocks will "continue to work until it stops working." If you don't pay attention to your portfolio's overall tech weighting, that vague endgame could turn out to be pretty ugly.