Pleasanton cloud-software company Workday increased the price range for shares in its initial public offering Tuesday, pushing the company's possible valuation past $4 billion in the most anticipated Silicon Valley debut scheduled for the rest of the year.

Workday originally filed for its IPO privately last summer, utilizing provisions of the federal JOBS Act to avoid public scrutiny, but gave that route up quickly and filed in August for an IPO of as much as $400 million. On Oct. 1, the company publicly filed plans to offer almost 23 million shares at $21 to $24 apiece, which would have brought in a maximum return of $546 million and valuation of $3.85 billion.

In an updated regulatory filing Tuesday, Workday increased that range to $24 to $26; at the high point, Workday would bring in $591.5 million at a valuation of nearly $4.2 billion.

Workday was founded in 2005 by former PeopleSoft executives Aneel Bhusri and David Duffield, who departed the similar company after it was acquired by Redwood City software giant Oracle (ORCL). The company offers human-resources software stored on its own servers, a popular offering known as cloud software and software as a service, or SaaS.

Cloud software companies have been popular targets for acquisitions by larger software companies, with Oracle, SAP and IBM spending billions recently on Bay Area companies like SuccessFactors, Taleo and Ariba. Enterprise software companies have also proven successful in an IPO market that has been overshadowed by Facebook's struggles -- Silicon Valley cloud software companies Jive Software, Infoblox and Palo Alto Networks have found eager investors with their offerings in the past year.

Co-CEOs Bhusri and Duffield chose to go the second route after their experience in seeing PeopleSoft swallowed up by Oracle, establishing a dual-class stock structure that will give the co-founders control over about two-thirds of the voting rights in the company, similar to Facebook's structure that gives CEO and cofounder Mark Zuckerberg strong control over the future of the Menlo Park social-networking company.

Investors seem eager for the offering, with IPO Boutique senior managing partner Scott Sweet saying Tuesday that Workday "will be the biggest cloud-based tech IPO this year."

"The institutions are coming in with monstrous orders and are willing to pay more than the prevailing price range. They want the deal very badly," Sweet told Bloomberg News.

The company has yet to turn a profit but shows the revenue growth that investors crave in an IPO, with overall revenues rising from $25.2 million to $68.1 million to $134.4 million in the last three full fiscal years. In the first six months of the 2012 fiscal year, that growth continued with revenues of $119.5 million, though losses totaled $47.3 million.

All the shares being sold in Workday's IPO come from the company, with no early investors or executives selling their shares, so all of the proceeds will go back into the company, which plans to use the cash for general business purposes, according to its filing. The company is expected to establish a final price for its shares on Thursday and begin trading on the New York Stock Exchange under the symbol WDAY on Friday.

Contact Jeremy C. Owens at 408-920-5876; follow him at Twitter.com/mercbizbreak.