Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Investors hate uncertainty, and right now, they're suffering from more of it than ever. Just when many thought that the future course of interest rate policy would be determined once and for all by now, Fed officials continue to give conflicting views of what the future might bring for quantitative easing. Moreover, arguments about the debt ceiling and the federal budget are bringing back bad memories of past confrontations between Congress and the president. The Dow Jones Industrials (INDEX: ^DJI) responded to all that uncertainty with an almost 50-point loss, while the S&P 500 (INDEX: ^GSPC) had an even larger half-percent drop.

Goldman Sachs (NYSE: GS) celebrated its first day as a Dow component by leading the declining stocks in the average, with stock falling $4.50 to $165.25. The big question facing Goldman is whether the bond market's rate run-up will contribute to trading losses that could hit earnings. Goldman won't see the losses that some of its retail-banking peers will face from reduced mortgage lending activity, but bonds held for its own account could nevertheless produce losses. More importantly, a decline in bond-issuing activity as bond yields rise could eat into its underwriting income.

JPMorgan Chase (NYSE: JPM) also fell sharply, finishing down 2.5%. In addition to some of the same woes that Goldman and the rest of the banking sector faced today, JPMorgan also got the news that it could face a Justice Department lawsuit as early as tomorrow over alleged securities-law violations connected with its sales of mortgage-backed securities. The suit shows that even five years after the financial crisis, questions about bank behavior over subprime mortgage loans still persist and could come back to bite JPMorgan and its peers.

Finally, Coca-Cola (NYSE: KO) posted a loss of nearly 2%. News of a marketing mishap last week didn't add any enthusiasm among Coke investors, but from a bigger-picture view, the soft-drink giant still faces the challenge of reconciling sluggish growth with an earnings multiple above 20. The Dow's record run has lifted many of its components' share prices, but Coke could be more vulnerable than most if rates start to rise and make even its healthy dividend look less bubbly.

Will Goldman and JPMorgan redeem themselves in the long run?
Despite today's losses, banks like JPMorgan and Goldman have soared in recent years. But even after those gains, bargains of a lifetime are still available. You just need to know where to look. The Motley Fool's new report "Finding the Next Bank Stock Home Run" will show you how and where to find these deals. It's completely free -- click here to get started.

Fool contributor Dan Caplinger owns warrants on JPMorgan Chase. You can follow him on Twitter @DanCaplinger. The Motley Fool recommends Coca-Cola and Goldman Sachs and owns shares of JPMorgan Chase. 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.