Who's Buying Now?

It's time once again to check the most interesting insider purchases of the week. After reading through numerous filings using insider tracking tool Form 4 Oracle, here are my top five today.

The week's buying

Please stop quoting Peter Lynch
I'm going to take a risk today. I'm going to refute Peter Lynch. Or, at least, the common reference to Lynch when it comes to insider buying, which says that insiders sell for all sorts of reasons but they buy for only one -- because they believe the stock is cheap.

There's admirable insight in that paraphrasing. What I despise is the logical fallacy it creates, which goes something like this:

• Insiders think the stock is cheap.
• Insiders know the business better than I do.
• The stock must be cheap.
• I must buy, too.

Insider buying is never, ever a perfect indicator. Witness IndyMac Bancorp (NYSE: IMB) and Luminent Mortgage Capital. Executives at both firms put significant wealth on the line and lost. They were small-f fooled, as I was when last year I wrote about how Luminent looked cheap.

But, of course, it wasn't. Context mattered. What I didn't know with Luminent and IndyMac is how much lying went into the so-called "liar loans" these firms were backing. Insiders, apparently, didn't know, either.

Here's my point. When assessing the importance of insider buying, look at the questions that exist about the business you're analyzing. How might the buying you're witnessing answer those questions?

Time for a dose of Mylan?
Let's run through an example. This week's top pick, generic drug producer Mylan Labs, faces two big questions from investors:

• Can it successfully integrate and draw value from recent acquisitions?
• Can management handle the debt it assumed to fund those deals?

Foolish colleague Brian Orelli argues that it's possible. Quoting from his recent take on the company:

Mylan's new larger size should help it compete against the two big guns in generic drugs: Teva Pharmaceutical (Nasdaq: TEVA) and Novartis. If it can trim the fat, Mylan should make for a good long-term investment.

Notice that his argument doesn't hinge on insider buying. (Though it could: Five different insiders, including four C-level executives, have bought shares in the last week.)

What he's saying is that, by acquiring measurable scale, Mylan has given itself the resources to compete against well-heeled peers. If evidence of fiscal discipline follows, higher returns should as well.

Thus, with Mylan, insider buying is but one data point in the process of analyzing its worth as an investment. My argument for Luminent was a lot thinner and closer to the logical fallacy I lampooned at the open.

Interestingly, our 86,000-strong Motley Fool CAPS community seems to know the difference. Whereas Luminent earned just two stars at the time of my write-up, Mylan gets four today:

Color me intrigued. I'll be adding Mylan to my CAPS watch list today.

There's your update. See you back here next week, when we dig through more insider filings in search of the next home run stock.

Get the inside scoop on stocks of all sizes with related Foolishness:

• Find out who was buying last time.
• You never have to think about great stocks.
• Not listening to Buffett cost one Fool thousands.
• Perhaps it's finally time you hedged against the crash?