We’re back in the middle of earnings season, and the 10% Promise team is hard at work reporting on all of the big moves happening in the market. After looking through the long list of stocks that moved this week, here are three things the market taught me this week.

Citron Research is becoming a market power, sort of
If you haven’t heard of Citron Research, you should at least be aware of who they are -- especially if you invest in Chinese stocks. Citron is basically a research house that generally takes short views on a company and releases a research report on its web site.

Citron has developed a reputation for unearthing issues at companies that most investors have blindly trusted. Targets have included Deer Consumer Products (Nasdaq: DEER), China MediaExpress (Nasdaq: CCME), and this week Longtop Financial Technologies (NYSE: LFT) joined the list. Citron released a negative research report on Longtop on Tuesday. By Wednesday, shares had lost nearly 30% of their value before rebounding sharply the rest of the week.

I did note that on Citron's website the company has the following disclaimer: “At any times the principals of Citron might hold a position in any of the securities profiled on the site. Citron will not report when a position is initiated or covered.” That leaves open the possibility that the firm is profiting from the effects of its own research.

For now, the main point isn’t whether Citron was right but rather that the market is now paying attention to what it says in the short-term. This fad may come and go, but for now, investors need to at least be aware of Citron and its influence on the market.

Earthquake aftershocks strike
The impact of the earthquake and tsunami in Japan has been relatively mild so far, but as earnings come out there are trickles of supply disruptions. Rockwell Automation (NYSE: ROK) and Group 1 Automotive (NYSE: GPI) hit our plunged list this week on concerns that problems in Japan would hurt profitability in the future. Disruptions will likely be temporary, so if the market panics over a temporary drop in sales, it might be time to pounce on the opportunity to buy shares on sale.

We can’t rid ourselves of rating agencies
Now for the earnings beat and stock pop that made say, “Really?”

Moody’s (NYSE: MCO) crushed estimates on higher bond issuance as investors apparently can’t figure out a better way to assess risk than the letter grades that rating agencies hand out. I thought we had decided that Moody’s and McGraw Hill (NYSE: MHP) division of Standard & Poor’s played a big part in the financial crisis and that we needed to find a better way to assess risk, but it appears that was just a dream. As fellow Fool Morgan Housel recently pointed out, these are still the most powerful companies in the world. Too bad!

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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 CAPS picks at TMFFlushDraw.

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