While insider selling has reached new highs this year -- particularly among the executives of Internet and technology firms -- one sector of the market has actually seen a fair amount of insider buying: energy companies.

With the exception of

oil services insiders, energy-sector execs have been among the year's most steadfast supporters of their companies' shares, and of those, the most active have been those in the natural gas industry. For example, at

Southern Union

( SUG), seven insiders have acquired more than 150,000 shares since March. At prices ranging from 13 to as high as 16 3/4, that's an investment of more than $2 million.

Don't expect such flamboyance as a rule. Energy industry insiders are notoriously discreet. At

Piedmont Natural Gas

(PNY)

, five insiders picked up a more modest 19,000 shares in late February and March in the 24 to 25 range. Even more mild-mannered, four insiders recently picked up 3,835 shares of

Northwest Natural Gas

(NWNG)

at around 20. Finally, along the same lines, three

Peoples Energy

(PGL)

insiders purchased 3,348 shares in the mid-to-high 20s.

These numbers may not strike you as overwhelming, but taken as a whole, insiders in the sector are hinting at a very strong trend. The kind of trend that gets you thinking.

After all, with oil clinging to 30 bucks a barrel, the big question on everyone's mind is how long can it be until folks start sniffing around for alternative fuels? Natural gas already plays an ever-growing role in the production of electricity (as Howard Simons

points out). And have you heard that some of America's biggest factories can already shift their primary energy source from oil to natural gas on demand?

Then again, maybe in a market as adept at taking your money as this one, these high-yield stocks simply strike insiders as attractive investments. With the exception of Southern Union, all of the above issues sport dividend yields of 5% or more.

On Order

A few weeks back we introduced our evolving approach to

lockup expirations. Increasingly, we view lockups as dynamic, lasting at least until the bulk of the unregistered shares is either sold, or in the (stronger) hands of "true" insiders. In other words, we are as concerned with

who

holds the potential supply as we are with the magnitude of the overhang itself.

With this in mind, there are reasons to believe that, should sentiment shift in its favor,

pcOrder.com

(PCOR)

-- limited float and all -- might face an easier road to recovery than many of its peers.

First, a little history: When pcOrder.com's lockup expired last August, few expected a lot of selling. This was because company insiders and

Trilogy Software

, an outside though interested investor, held most of the unlocked shares. In fact, outside of a 2.5 million-share secondary in December (in which majority holder Trilogy shed more than 1.8 million shares), very few shares have changed hands.

In contrast, pcOrder.com insiders seem more inclined to

acquire

shares. Chairman and CEO Ross Cooley, for example, exercised options to acquire 50,000 shares. Cooley, a seasoned industry vet and longtime

Compaq

( CPQ) exec, had previously sold 150,000 shares throughout '99 at prices ranging from $43 to $50 per share. The recent acquisition is his first since joining the company last year. Though not technically an insider, Lang Gerhard, managing partner for

West Highland Partners

, and

Buttonwood Partners

purchased 618,000 shares on the open market.

Why would Gerhard establish a nearly 7% stake in pcOrder? Some have speculated that investors overreacted to news that its major customer,

Ingram Micro

(IM)

, had signed a content-licensing agreement with pcOrder competitor

CNET

(CNET) - Get Report

. In fact, to hear it from either Ingram Micro or pcOrder, the deal changes nothing.

The market clearly disagrees -- the shares have fallen 76% since the release of the news on Feb. 14, but with Compaq,

Hewlett-Packard

( HWP) and

IBM

(IBM) - Get Report

all counted among its long list of customers, it seems unlikely that pcOrder has hitched its wagon entirely to Ingram Micro.

More likely, the Ingram Micro incident merely pushed pcOrder to the head of the B2B lemming line. At least restricted holders of pcOrder haven't sold at the lower prices.

The wildcard, of course, is Trilogy. Will Trilogy, founded by pcOrder President and COO Christina Jones, unload its holdings to the detriment of pcOrder investors? If so, look out below. If not, should pcOrder catch a wave, it's a good bet the ride won't be squashed by a glut of restricted stock hitting the market -- at least not in the early stages.

Bob Gabele has been tracking and analyzing insider trading since 1978, most recently for First Call/Thomson Financial. This column is not meant as investment advice; it is instead meant to provide insight into the methods of insider trading. At time of publication, Gabele held no position in any of the companies discussed in this column, although holdings can change at any time. Under no circumstances does the information in this column represent a recommendation to buy or sell stocks. Gabele appreciates your feedback at

rgabele@thestreet.com.