Profit estimates for America's largest companies are turning ever-so-slightly sweeter. As of the end of March, operating earnings underlying the S&P 500 index were forecast to total $20.45 for the third quarter, which runs through the end of this month. By the end of June, that estimate had increased by 27 cents. Now it's another four cents higher, at $20.76. If met, that forecast would mark a slight decline from the second quarter (as is typical) but a 32% improvement from a year earlier.

The three companies below are in the middle of the momentum. For each, current-quarter estimates for not only earnings, but also sales, have increased over the past four weeks.

Good earnings news alone can sometimes be attributed to mere cost cutting, but when it's accompanied by brighter sales, it's often a sign of solid customer demand. The average analyst recommendation for these stocks -- buy, hold and so on -- has also improved in recent weeks.

Caterpillar

Caterpillar (CAT) shares sell for more than 20 times this year's earnings forecast, a sizable premium to the broad stock market. Investors must know that this year's earnings forecast of $3.63 isn't nearly representative of what the company can earn during a good year. Eying a slow but steady recovery in global demand for earthmoving equipment and parts, Wall Street analysts expect the company to earn more than $5 a share next year and about $6 a share in 2012. In a meeting last month with analysts, Caterpillar chief Doug Oberhelman restated his plan to reach earnings of $8 to $12 a share by 2012. Part of the plan is to add production capacity, so that sales aren't constrained by manufacturing delays during the next peak in demand, as has happened in the past. The main risk to the plan, of course, is that the expected demand doesn't materialize as soon as hoped. Shares at their current price offer a 2.5% dividend yield.

Dell

Dell (DELL) was outbid by Hewlett-Packard (HPQ) in its 18-day attempt to buy 3PAR, a closely-held maker of data storage equipment. The acquisition would have allowed Dell to sell its own line of external hard disks to high-volume users, but for now it will have to continue reselling other manufacturers' drives, collecting only slim margins for itself. A $72 million breakup fee offers a bit of consolation. Perhaps recent operating results do, too. Sales last quarter exceeded Wall Street's estimates and free cash flow reached $1.2 billion, or about 5% of the company's stock market value. Cash on hand now accounts for about one-quarter of the stock price, and shares sell for less than 10 times earnings.

Bed Bath & Beyond

Linens n' Things went bankrupt in December 2008, removing a key competitor for Bed Bath & Beyond (BBBY). That has helped the company maintain respectable margins, despite a generally sluggish pace of sales for house wares. Bed Bath & Beyond turned about 13 cents of each of sales dollar into operating profit over the past year, versus less than eight cents for Macy's (M) and Target (TGT). According to Jefferies & Company analyst John Marrin, the firm has significant growth potential for a company of its size. It now has just over 1,100 stores, with nearly 1,000 of them operating under its namesake brand. That leaves the company's prospering Buy Buy Baby and Christmas Tree Shops chains with few stores. In an August note to investors initiating coverage of the shares with a "buy" recommendation, Marrin wrote that the store count could eventually double as Bed Bath & Beyond builds its small chains into national brands and takes share formerly held by Linen n' Things. The company has close to $1.8 billion in cash on hand, which according to Marrin exceeds its operating needs by $1.5 billion, or 15% of its stock market value. That surplus suggests a wave of share repurchases is likely. Shares sell for 14 times earnings.