Bank of America (NYSE:BAC) is feeling pretty spiffy today as investors send its stock price incrementally higher since the market opened a very short time ago. With the big bank announcing earnings in two days, this could very easily have gone the other way -- but it didn't. For that, I believe, B of A has Citigroup (NYSE:C) to thank.

A harbinger of good news?
When peers JPMorgan Chase (NYSE:JPM) and Wells Fargo (NYSE:WFC) reported earnings last Friday, I thought things would look dismal for Bank of America this week. The reason? Despite decent reports, the two big banks showed that a slowdown in the mortgage refinance and origination markets has arrived, and likely isn't going away.

The reduction in business was apparent for Wells, and though JPMorgan managed to increase its mortgage volume from the last quarter of last year, CEO Jamie Dimon noted that the mortgage business was slowing. After all, I figured, if Wells Fargo is seeing a drop in production -- the bank that has seen the greatest mortgage production of all of the big banks for over a year now -- what does this say for B of A? Didn't CEO Brian Moynihan stress that his bank was stepping up this very thing in an effort to boost revenue and profits?

Enter Citigroup and its stellar report earlier today. Citi is often compared more closely with B of A, since both have been mortgage-lending laggards compared to Wells and JPMorgan, and both have been shedding costly add-ons that have been dragging down each bank's recovery. In Citi's case, too, a recent management shake-up may very well have dampened expectations for good news.

But Citi delivered the goods, beating on earnings and revenue -- and not by writing a slew of mortgages. Citi increased its income with higher revenue from Securities and Banking, which rose 24% year over year, and investment banking, up 22%. For this, Citi is feeling intense investor love today, and it has certainly earned it.

Is Citi's glow warming B of A, as well? I believe it is. Investors see that the same scenario could very well play out for Bank of America, and that is indeed quite possible. We will see soon enough, as the big guy reports earnings bright and early on Wednesday. Until then, I think the bank will be feeling some investor affection today, too.

As a group, the big banks are so far having a pretty good day. Things could change, though, so it is important to keep in mind that it is the overall performance of a stock that really counts. As Foolish, long-term investors, we recognize the fact that one-day changes in share price don't make or break an investment. Even stocks have good days and bad days, so it's important to realize that sometimes they're not portents of dire news, but merely squiggles that we can safely ignore. 

Fool contributor Amanda Alix has no position in any stocks mentioned. 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 disclosure policy.