Yesterday's plunge in the Dow Jones Industrials (DJINDICES:^DJI) has brought on a predictable flurry of discussion about whether a long-awaited correction may finally be in the cards for the stock market. This morning's follow-through selling certainly supports that notion, as the market ignored a slight increase in existing-home sales and news that housing inventories were at their lowest levels since 2000. However, with Zillow estimating that 2 million homeowners worked their way out of being underwater on their mortgages during 2012, one big overhang holding back consumers may be dissipating, which could point to longer-term bullish prospects for the economy. In the grips of fear, though, the Dow is down 61 points as of 10:55 a.m. EST. Broader markets have fallen a bit more than the Dow, and international markets are responding still more negatively to yesterday's U.S. market sell-off.

Among the Dow's worst performers is Caterpillar (NYSE:CAT), which is down 2%. Yesterday the company reported that global sales in the three months ending in January dropped 4%, marking a second straight monthly decline after sales had risen steadily for more than two and a half years. Although Latin America and the Europe-Africa-Middle East segment improved, sales in North America and the Asia-Pacific region were both down by double-digit percentages. With Caterpillar focusing on those latter markets for growth prospects, it needs those trends to reverse in order to see better share-price performance again.

Elsewhere, Safeway (NYSE:SWY) climbed almost 7% after reporting strong earnings, as net income rose 13%. The grocery retailer's store loyalty program helped the chain boost sales by 1.2% during the quarter, with same-store sales excluding gas purchases rising by 0.8%. Still, the grocery business is extremely competitive right now, and with big-box retailers, organic and health-conscious niche grocers, and traditional rivals all fighting for business, Safeway must continue to fight hard to keep moving higher.

Finally, Groupon (NASDAQ:GRPN) jumped 5.7% after getting a rating upgrade from Piper Jaffray. Although many investors feel the daily-deal play has run its course in the U.S., Piper pointed to strength in international markets as a potential driver for future growth. The company has benefited from increased analyst awareness lately, with many seeming to see the beaten-down shares as a long-term value proposition, given the company's well-known name.

Fool contributor Dan Caplinger has no position in any stocks mentioned. You can follow him on Twitter @DanCaplinger. The Motley Fool recommends Zillow. The Motley Fool owns shares of Zillow. 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.