My take1

WaMu Shows, Again, Smart Money Can Be Wrong

"don’t make a financial company your largest position"

I totally agree. Financial companies don't actually make or build or create something tangible. What they deal with is papers and paper money, the paper money can grow a lot in value, but it can also vanish in an instant.

Instead, choose companies that make something people can see and use, and something that actually does something in real life. Those companies rarely go bankrupt. For example, I never heard that a semiconductor hardware company or chip company went bankrupt. When things go really bad, they get bought by a competitor with usally more than 50% premium on depressed stock value. So, actually, you can make a lot of money out of troubled tech companies.

Don't build your portfolio on vaporware. I didn't have to learn this lesson, my common sense has worked well for me.