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: Shares of BOK Financial (Nasdaq: BOKF) surged as high as 16% in early Monday trading after a Wall Street analyst upgraded the regional bank from "hold" to "buy."

So what: Along with the upgrade, Stifel Nicolaus upped its price target on the shares to $56, representing about 23% worth of upside to their previous close. At the time of publication, BOK shares are well off their highs of the day (only up about 3% now), so much of that upside remains intact.

Now what: Fools know to take analyst upgrades with a grain of salt, but BOK seems worth looking into. Thanks to disciplined underwriting, a solid financial position, and wide product diversification, BOK remains much more protected from heavy loan losses than many other regional banks. With the stock still down more than 13% in August alone and sporting a relatively safe 2%-plus dividend yield, BOK might be a timely pick, as well.   

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