Most of the big American banks are up today, but not quite like Citigroup (C 2.48%), which is leading the charge in a major way. A little past the midday mark, the bank is up 2.87% already -- and seemingly climbing higher still.

The tale of the tickers
Here's where some of banking's biggest guns are shaking out so far today:

  • Bank of America is up a hearty 2.7%.
  • Goldman Sachs is up a healthy 1.32%, as is JPMorgan Chase, which is up 1.19%.
  • Up by 0.43%, Wells Fargo is also doing well.

With the Dow Jones Industrial Average is currently up 0.36%, the Nasdaq up 0.04%, and the S&P 500 up by 0.26%, all of the major market indices are rising along with these bellwether financials. So with the market mainly climbing today, is Citi just riding the wave and then some, or is there some breaking news driving today's share-price jump?

I see a better business model in your future
The only thing in the news today for Citi is an announcement that the superbank is selling half its stake in Mexico's largest airline, Grupo Aeromexico SAB. Details are scant, and the company has made no comment, but it could be that investors see this as further sign the bank is streamlining its operations and trying to get back to a business model driven by banking basics.

Like its peer B of A, Citi emerged from the financial crisis much more shaky than, say, JPMorgan or Wells Fargo, and it has spent the last few years trying to get back on its banking game. Selling off questionable assets, like a large stake in a foreign airline, or getting out of an awkward partnership with a peer, like agreeing to sell the remainder of Morgan Stanley Smith Barney back to Morgan Stanley, are the kinds of things today's post-crash bank investors like to see.

Otherwise, in moments of market mayhem -- whether your favorite stock is up big or down even bigger -- remember this Motley Fool motto (my personal favorite): "Get rich slowly." You're in this for the long term, Fool. So feel free to check on your stocks every day, but barring fundamental changes in the company, take whatever you see with a grain of salt -- sometimes a very large one.