Yahoo Inc. clamped down on its political lobbying expenses in the third quarter even as the Internet company started to muster support for its proposed partnership with rival Microsoft Corp., according to a recent disclosure form.

The Sunnyvale, Calif.-based company spent $510,000 trying to influence lawmakers and regulators on a variety of issues during the July-September period. That represented an 11 percent decrease from lobbying expenses of $570,000 in the same period last year.

Through the first nine months of the year, Yahoo spent nearly $1.5 million on lobbying, down 21 percent from the year-ago period.

Yahoo has become more frugal during the past year as its revenue has shriveled amid the worst U.S. recession in 70 years. The tough times have crimped the budgets of online advertisers, the main source of Yahoo's revenue.

As part of its cost-cutting, Yahoo has eliminated about 2,000 jobs _ about 13 percent of its work force _ in the past year.

Yahoo hopes to save even more money by relying on Microsoft's technology to power the search engine on its Web site. The proposed alliance, forged in July after months of intermittent negotiations, still needs regulatory approval.

As part of its initial efforts to drum up support, Yahoo tried to educate Congress about the benefits of a Microsoft partnership, according to a disclosure form filed Oct. 20 with the House clerk's office.

Microsoft didn't list the Yahoo partnership on its third-quarter lobbying agenda.

Yahoo also spent money trying to convince Congress that a proposed legal settlement giving Google Inc. the digital rights to millions of out-of-print books shouldn't be allowed. Google, the Internet search leader, is expected to file revisions to the settlement late Monday in an effort to address legal concerns raised by the U.S. Justice Department.

Besides Congress, Yahoo lobbied the Federal Trade Commission, Commerce Department, State Department and the White House.

The lobbying issues included: online privacy and child protection, combating Internet crime, international taxes, possible tax fallout from proposed changes to health insurance and shareholder rights.

Among those registered to lobby for Yahoo were: David Hantman, former chief of staff for Sen. Charles Schumer, D-N.Y.; and Margaret Stewart, former director of legislative affairs for the Office of Management and Budget.