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.

The Dow Jones Industrials (DJINDICES:^DJI) ended the day down 133 points, with most of those losses coming in the last couple hours of the day as investors expressed their disappointment at the ongoing stalemate in Washington. With lawmakers in both chambers of Congress still wrangling over the particulars of a deal that would reopen the government and prevent a debt default, their willingness to push their negotiations to the brink of key deadlines didn't sit well with nervous shareholders.

Indeed, judging from the worst performers in the Dow, investors seem to acknowledge that the general public shares their views about Washington's lack of response to the situation. Home Depot (NYSE:HD) fell 1.5% despite earning an upgrade in two key credit ratings from Standard & Poor's. Reflecting the home-improvement retailer's improving revenue and income prospects, S&P boosted its corporate credit rating and its short-term rating by one notch each. Yet the decline suggests worries that even if lawmakers resolve the shutdown now, the lingering impact on consumers could reverse the gains that Home Depot has fought so hard to achieve.

Similarly, Procter & Gamble (NYSE:PG) declined almost 1.5%. Interesting reports from the Wall Street Journal discussed how online retailer Amazon.com (NASDAQ:AMZN) is using P&G's warehouses to help it improve its logistics and deliver products faster to its customers. The move might sound like a positive for P&G, but if it alienates Amazon's retail competitors, it could end up backfiring on the consumer-products giant and push some of its key customers to prefer products from P&G's rivals. For its part, if Amazon forges alliances with P&G's competitors, then other retail outlets won't have anywhere else to turn to protest P&G's moves.

It's too early to tell whether Home Depot and P&G have anything really to worry about on the consumer-spending front, as the impact from the shutdown will take months to manifest fully. Yet investors are right to be cautious about their prospects going forward until consumers are able to adapt to new economic conditions and react appropriately.

Fool contributor Dan Caplinger has no position in any stocks mentioned. You can follow him on Twitter @DanCaplinger. The Motley Fool recommends Amazon.com, Home Depot, and Procter & Gamble. The Motley Fool owns shares of Amazon.com. 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.