SAN FRANCISCO (AP) – Oracle Corp. is putting more money into its pursuit of rival software maker PeopleSoft Inc., boosting its bid to $6.3 billion in a push to overcome PeopleSoft management’s opposition to the deal.

Meetings with PeopleSoft’s largest shareholders this week prompted the sweeter all-cash bid of $19.50 per share, Oracle chief financial officer Jeff Henley said. The new offer Wednesday was 22 percent higher than the $16 Oracle initially proposed for PeopleSoft.

Oracle’s sweetened offer is the latest salvo in the fiercely contested business software niche, which builds computer programs to run giant databases so corporate clients can store customers’ credit card and other personal information, process transactions online or compile personnel data on internal Web sites.

Germany’s SAP AG dominates the market, followed by Oracle, PeopleSoft and about 3,000 smaller vendors.

PeopleSoft issued a statement saying its board of directors would discuss the new offer and make a recommendation “in due course,” but urged shareholders not to take any immediate action.

“The board concluded that the original offer dramatically undervalues the company based on its financial performance, continued market leadership and significant future opportunities,” the statement said.

As PeopleSoft shareholders prepare to vote on the Oracle bid July 7, the company is turning to some of its largest customers for help, running newspaper ads Wednesday in which Toyota Motor and Nextel Communications praise PeopleSoft. Chicago-based Distributors and Manufacturers’ User Group, which represents 300 manufacturing companies, urged PeopleSoft’s board of directors to reject Oracle’s bid.

The biggest impediment to a takeover is a “poison pill” provision PeopleSoft’s management could activate. Considered an extreme measure, the anti-takeover defense typically fends off unwelcome suitors by issuing new shares that boost the cost of the deal.

Ken Marlin, managing director at New York-based media and technology investment bank Marlin & Associates, said Oracle’s latest offer is “quite fair.”

“This reaffirms what (Oracle chairman) Larry Ellison has been saying for quite some time – that his offer is serious,” Marlin said.

Pleasanton-based PeopleSoft announced a plan June 2 to acquire Denver-based J.D. Edwards & Co. in a stock swap valued at $1.7 billion. Oracle, based in Redwood Shores, launched its takeover bid four days later, offering $5.1 billion to buy PeopleSoft without J.D. Edwards.

PeopleSoft executives said joining with Oracle would be difficult, if not impossible, because regulators would raise too many questions about how the deal would affect competition in the $20 billion market for business software.

Industry analysts say PeopleSoft executives – many of whom defected from Oracle – would bristle under Ellison. Oracle and PeopleSoft have long had an acrimonious relationship, marked by sniping between Ellison and PeopleSoft chief executive Craig Conway, who worked under Ellison from 1985 to 1993.

PeopleSoft filed a lawsuit in state court alleging the bid is a “sham” offer designed to destroy the company. J.D. Edwards also sued Oracle, seeking $1.7 billion, plus unspecified punitive damages, for trying to interfere with its PeopleSoft deal. Oracle said the suit is “frivolous.”

Oracle said Wednesday it plans to sue PeopleSoft, its board of directors and J.D. Edwards in Delaware in response to “their collective efforts to eliminate PeopleSoft shareholders’ ability to accept Oracle’s tender offer.”

It’s unclear how 5,100 PeopleSoft customers would fare in a takeover. Big clients such as government agencies and Fortune 500 corporations spend hundreds of millions of dollars to install proprietary business software; switching can become a costly, technical morass.

Connecticut filed a lawsuit against Oracle on Wednesday to scuttle the takeover. Gov. John Rowland said the state has spent $80 million to upgrade its human resources and payroll systems using PeopleSoft software. If Oracle takes over and discontinues the PeopleSoft product line, it would cost the state tens of millions of dollars.

Henley said Oracle would not eliminate the PeopleSoft brand but would not offer PeopleSoft products to new clients.

“We intend to support these products for a long time,” Henley said. He also noted that PeopleSoft’s consulting projects would “naturally wind down” over the next nine to 12 months but that Oracle would support existing projects.