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 Spanish banking giant Banco Santander (NYSE: STD) shot up as much as 12% in intraday trading, after Portugal conducted a $1.6 billion bond auction.

So what: Optimists exulted that the Portuguese auction proved the country wouldn't be next in line for a eurozone bailout. For Banco Santander, a not-floundering Portugal means that its eurozone sovereign debt holdings may not get crushed, and that its financing costs won't skyrocket. Of course, Santander isn't alone in celebration. Shares of fellow Spanish bank Banco Bilbao Viscaya Argentaria (NYSE: BBVA) also rose significantly; ditto National Bank of Greece (NYSE: NBG).

Now what: This is hardly the end of Europe's sad story. While many hail today's Portugal auction as "successful," some, including PIMCO's Bill Gross, aren't so impressed. Today's news is a step in the right direction, but Portugal and the rest of the PIIGS (Portugal, Ireland, Italy, Greece, and Spain) need to show continued progress toward sound financial footing if they hope to retain whatever shreds of confidence bond investors have left.

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