Financial forecasts for America s big companies continue to improve, on the whole. Over the past four weeks, more S&P 500 members have had their earnings projections raised by Wall Street than lowered. The same goes for sales estimates.

That s a good sign. Companies with forecast boosts this quarter are more likely than not to attract additional bumps next quarter, and their shares tend to perform handsomely for months to come, studies show. Of course, that pattern is unlikely to hold if the broad economy sinks back into recession. Investors must decide for themselves if the current pace of earnings growth seems reasonable and sustainable. If calendar 2010 forecasts are met, earnings for S&P 500 companies (not counting one-time charges) will have nearly doubled from their recent low reached during the four quarters ended September 2009, and will amount to 80% of record profits amassed during the four quarters ended June 2007.

Below are listed three S&P 500 members whose sales and earnings forecasts for their current fiscal year have increased meaningfully within the past four weeks.

John Deere

Tractor maker John Deere (DE) made a mockery of Wall Street estimates when it reported results for its first fiscal quarter in mid-February. Analysts were looking for earnings of 19 cents a share. They got 57 cents. Management raised its full-year profit projection to $1.3 billion from $900 million. Dealers seem to be replenishing lean inventories. Shares of John Deere have nearly doubled in price in a year, shrinking the dividend yield to 1.9%, a touch less than the broad market s yield. The company will have to produce plenty more good news to justify its current price. The stock goes for 19 times forecast earnings for Deere s fiscal 2010, which runs through the end of October. It s about 12 times the company s record earnings produced in 2008.

Analog Devices

If analog sounds old-fashioned, it s only because analog music recordings (records) were mostly replaced by digital ones (compact discs, downloadable files) during the past few decades. When the term is applied to integrated circuits, the building blocks of microchips, it refers to ones that help turn real-world sensations like light, sound and pressure into electrical signals. Smart phones, medical imaging machines, windmills, cars and plenty of other technologies rely on circuits made by companies like Analog Devices (ADI) . In another sign that industrial demand is picking up, Analog reported 26% sales growth in its most recent quarter versus a year earlier. Margins soared, thanks to cost-cutting and the returns to scale that typify the chip business. Shares sell for 15 times this fiscal year s earnings forecast and come with a 2.9% dividend yield.

Rowan Companies

Rowan Companies (RDC) is a contract driller with 23 jack-up rigs mobile platforms with legs that can be lowered to rest on the sea floor. The company builds its own rigs and has five more under construction. The firm also has 32 land rigs. Rowan s sales plunged last year as energy demand fell and contractors were forced to reduce prices, but demand and pricing have recently improved. Shares of the company have outperformed those of industry peers in recent weeks. That might be related to analysts comments about the company s attractiveness to potential suitors in the jack-up industry or customers strong preference for high-grade rigs like the ones in Rowan s fleet. Shares sell for 11 times forecast 2010 earnings, with no dividend.