As a member of our 10% Promise team, I see a lot of wild swings in the market. Sometimes there's an easy explanation and sometimes the market knocks us for a loop without telling us why. But every week I learn something new. Here are a few things the market taught me this week.

Sam Adams, please
I keep thinking Boston Beer (NYSE: SAM) will run out of steam, but the maker of Sam Adams just keeps pumping out great quarterly numbers. On Wednesday, the stock jumped 14% after the company released great earnings and bumped guidance higher. Apparently I'm not the only one turning down cheap light beer in favor of a tasty craft brew. How long can this trend continue?

AIG is back
Shares of AIG jumped earlier this week on comments from Chairman Steve Miller that the company may shift into growth mode from survival mode. But I also got a surprise when Timothy Geithner said he thought the entire financial bailout would cost less than $25 billion. It was once unfathomable that the government would get most of the bailout/taxpayer money back, so we should all be dancing in the streets after hearing this news.

The electronics world is turning upside down
The market kicked Best Buy (NYSE: BBY) and hhgregg (NYSE: HGG) to the curb faster than you can say "Geek Squad" after hearing Best Buy lost market share. I guess this isn't terribly surprising when you think about it. These days, Target carries comparable electronics to Best Buy, and you can pick up some milk and eggs on your way out. I love going to Best Buy but more as a sightseeing trip than a place I have to buy a big-ticket electronics item. Maybe that would change if Best Buy and hhgregg started carrying grocery items?

Knowing the rules is half the battle
Shares of optionsXpress (Nasdaq: OXPS) were all over the place Tuesday on confusion about an upcoming dividend. The company clarified the issue Wednesday in a press release stating that because of a Nasdaq rule, the ex-dividend date will be Dec. 28 for shares outstanding on Dec. 13. I hadn't heard of Nasdaq Rule 11140(b)(2) until this week, but these are the things you learn in the market. Head still spinning? See the press release here.

Speaking of rules, Visa (NYSE: V) and MasterCard (NYSE: MA) were both knocked down yesterday when the market found out regulators were looking at capping debit card interchange fees at a much lower rate than expected. The fallout from the Dodd-Frank financial reform bill is starting to hit investors, and so far it doesn't feel very good.

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Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings, or follow his Motley Fool CAPS picks at TMFFlushDraw.

Best Buy, hhgregg, optionsXpress Holdings, and Boston Beer are Motley Fool Stock Advisor choices. Motley Fool Options has recommended buying calls on Best Buy, which is also a Motley Fool Inside Value recommendation. The Fool owns shares of Best Buy. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.