Could Citigroup (C 2.07%) stock be doing any better? The superbank's share price is up a big 3.71% this week, and investors may have several factors to thank.

Up, up, and away
First, let's have a quick look at exactly where Citi's peers and the markets are on this last day of trading for the week:

  • Bank of America is up a healthy 1.54%.
  • JPMorgan Chase is up an even more healthy 2.25%.
  • Wells Fargo is up an almost healthy 0.53%.

The markets are all in the green, as well, with the Dow Jones Industrial Average up 2.02%, the S&P 500 up 2.13%, and the Nasdaq Composite up 2.47%.

Foolish bottom line
For starters, Citi investors can thank a bit of a bounce coming off last's week's poor performance for this week's good performance.

Citi took a nosedive on Wednesday, along with its big four cohorts, that it never quite recovered from, and that happened for no apparent reason. So this week's performance may have been due, in part, to the market naturally resetting itself.

Citi also showed some chutzpah by filing a claim on Monday against Nasdaq OMX for the botched handling of the Facebook initial public offering. It doesn't look like the bank can claim massive amounts of money for damages, but investors may just have been happy to see Citi stepping up and going after monies they legitimately have coming to them. I know as an investor myself, I was happy to see the move.

Citi is also about to report first-quarter earnings. And after last quarter's strong performance, investors may be looking forward to hearing about the first quarter's. Again, I know I am.

Of course, the markets are all up this week, and Citi may just be going along for the ride. You know the way this investment thing goes: One week the market's up, the next it's down, and not for any seemingly good reason.

Just keep an eye on your company's fundamentals, and keep an eye on the long term, and before you know it, you're investing Foolishly.