Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: MGIC Investment (NYSE: MTG) dropped 20% in intraday trading after competitor PMI Group (NYSE: PMI) indicated it may shut down.

So what: PMI Group reported EPS of -$0.83, an improvement from -$1.11 in the year-ago quarter. The net loss amounted to $151 million. The improvement was driven by a $151 million gain on the sale of a discontinued operation and a $123 million improvement in the fair value of certain company debt.

Now what: Your Foolish servant tried to warn investors that monoline private mortgage insurers MGIC Investment, PMI Group, and Radian Group (NYSE: RDN) could be heading to good-for-nothing-but-a-tax-write-off status, i.e., zero. PMI Group stated it expects the number of states in which it is precluded from writing new business to "significantly increase” and it plans to meet with regulators to discuss “various capital initiatives the company is pursuing." In plain English, the company needs money to fund ongoing losses -- but it's running out.

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This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.