Salesforce.com Inc.'s (CRM) first-quarter profit nearly doubled on improved margins, but the company cut its fiscal-year 2010 revenue guidance, saying its new business signings for the quarter were lower than expected.

Shares, which have nearly doubled since November but remain down by more than a third for the past 12 months, were sold off in the after-market. At 5.43 p.m. Eastern they were trading down 7.4% at $36.70, after closing at $39.65.

Analysts have been concerned in recent months that the San Francisco-based company, which makes online business software, could face lower renewal rates and declining demand due to layoffs and economic weakness.

On a conference call with analysts, Salesforce.com Chief Financial Officer Graham Smith said that the weaker full year revenue view reflected the fact that first quarter signings were weaker than expected. The company is also seeing increasing fluctuation in its seasonal invoicing patterns, longer sales cycles and smaller initial deal deployments.

Smith said that better than expected earnings per share reflected tighter cost control during the first quarter.

Salesforce.com now sees fiscal-year revenue of $1.25 billion to $1.27 billion, down from February's lowered forecast of $1.3 billion to $1.33 billion. But the company raised its earnings view by 5 cents to 59 cents to 60 cents a share.

It also projected second-quarter earnings of 14 cents to 15 cents on revenue of $312 million to $313 million. Analysts surveyed by Thomson Reuters, on average, estimated 13 cents and $319 million, respectively.

For the period ended April 30, Salesforce.com reported earnings of $18.4 million, or 15 cents a share, up from $9.6 million, or 8 cents a share, a year earlier. Revenue grew 23% to $304.9 million.

In February, the company projected earnings of 10 cents to 11 cents a share on revenue of $304 million to $305 million.

Gross margin edged up to 79.7% from 79.3%. The company's paying customer base grew 7% to 59,300.

-By Shara Tibken and Jessica Hodgson, Dow Jones Newswires; 201-938-2168; shara.tibken@dowjones.com;