It was a week of ups and downs for Citigroup (NYSE:C), with the ups winning out as the last day of trading nears a close. News wise, there wasn't a whole lot going on with the country's second biggest bank this week, but there was one bright spot that may have helped lift the superbank aloft.

Big-bank and market roundup
But first, here's where Citi, its peers, and the markets are shaking out on the week:

  • Citi is up 3.18%.
  • Bank of America is up a big 4.63%.
  • At 0.61%, Wells Fargo is up a bit.
  • While shares in JPMorgan Chase rose a solid 2.35%.

The markets are all up, as well, with the broader S&P 500 up by 0.81%, the narrower Dow Jones Industrial Average up 0.74%, and the Nasdaq Composite up 1.37%.

Smile, and the whole world smiles with you
When you're an equity investor, sometimes you latch onto anything positive -- or negative -- that hovers into view for the companies you've put your hard-earned money into, and that may help explain Citi's performance this week.

On Wednesday, The Wall Street Journal reported that Citi was suing Barclays (NYSE:BCS) for $141 million over currency-clearing services Citi rendered the British-banking giant in September 2008: specifically, the week right after Lehman Brothers declared bankruptcy. Barclays was in the process of trying to buy Lehman's North American businesses and needed the service, for which Citi demanded a deposit of $1 billion.

After all was said and done, Citi alleged that Barclays owed it $141 million to settle out the accounts of this risky deal from that messy week. But Barclays has so far refused to pay, and Citi has turned to the courts for satisfaction. 

I'm a Citi investor, and I personally liked seeing Citi going after monies due it. It made me feel like the people at the top are on their game and looking out for the long-term interests of the bank. And maybe other investors felt this way, too. Shares in the superbank did rise 2.7% on Wednesday, the stock's biggest one-day jump for the week.

But as you can see from the big-bank and market data, it was an up week overall, and it's entirely possible Citi went just went along for the ride -- and that this suit against Barclays had little if anything to do with the stock's strong performance. And that's probably the case in these situations more often than not.

In the short term, a company's share price can rise and fall dramatically, and it may be down more to market noise than anything else. Which is why we stress a long-term outlook here at The Motley Fool.

Focus on the fundamentals of the companies you're invested in, check in on your stocks once a month or even once a quarter, and leave the obsessive ticker-checking to the day traders. In the end, your portfolio will thank you, even if your broker won't. 

Fool contributor John Grgurich owns shares of Citigroup and JPMorgan Chase. Follow John's dispatches from the not-so-muddy trenches of high-finance and big-banking on Twitter @TMFGrgurich.

The Motley Fool recommends Wells Fargo. The Motley Fool owns shares of Bank of America, Citigroup, JPMorgan Chase, and Wells Fargo. 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 lovely disclosure policy.