Yahoo Inc's (YHOO.O) quarterly earnings fell short of Wall Street expectations on Monday in what may be the company's last financial report before it sells its core business.

Yahoo reported adjusted earnings of 9 cents per share, short of the 10 cents that analysts expected. It also announced a $482 million write-down on the value of Tumblr, the social media service that it acquired in 2013 for $1.1 billion.

Yahoo is in the process of auctioning off its search and advertising business, and is expected to choose a winner this week. The company said its board has made "great progress on strategic alternatives" but did not comment further on the auction process.

Verizon Communications Inc and AT&T Inc are said to be in the running to acquire the core business, along with private equity firm TPG Capital and a consortium led by Quicken Loans founder Dan Gilbert and backed by billionaire Warren Buffett.

Yahoo also owns large stakes in Chinese ecommerce giant Alibaba and Yahoo Japan, which are worth far more than the company's internet business.

Monday's earnings report showed the continued slide in Yahoo's business during the protracted sale process. After the Tumblr write-down, the company posted a net loss of $439.9 million, or 46 cents per share, compared with a loss of $21.6 million, or 2 cents per share, a year earlier.

Although total revenue rose to $1.31 billion from $1.24 billion a year earlier, the seeming improvement was the result of a change in the way the cost of acquiring traffic is counted. After deducting fees paid to partner websites for traffic, revenue fell to $841.2 million from $1.04 billion.

Estimating that Tumblr is worth "nothing" at this point, Ross Gerber, cofounder and CEO of Gerber Kawasaki Wealth and Investment Management, said potential buyers were likely bidding lower than Yahoo believes it is worth.

"I can't imagine why the sale process is taking so long, the only thing I can think of is it's being overpriced. This report doesn't further create an impression that paying up for these assets has any value," Gerber said.

Revenue in the company's emerging businesses, which Chief Executive Officer Marissa Mayer calls Mavens - mobile, video, native and social advertising - showed some life, rising 25.7 percent to $504 million in the second quarter ended June 30.

But the improvement in Mavens was offset by decreases in gross search revenue that is only expected to get worse, said B. Riley & Co analyst Sameet Sinha. Gross search revenue for the quarter was $765 million, down 17 percent from the same period last year.

"This is supposed to be the growth engine of the company, and at best it was up slightly year over year. That shows that even in high-growth categories like mobile and native they're losing their search impact," he said.

JMP Securities analyst Ronald Josey said search revenues are a significant portion of Yahoo's overall revenues and their continued decline could definitely be a factor in the sale negotiations.

"If search continues to decline as much as it has, that's something that's going to be called into question," he said.

In a conference call, Yahoo Chief Financial Officer Ken Goldman touted the company's cost-cutting efforts.

“Through excellent expenditure management of cost and capital, we achieved above the high-end of our guidance on adjusted EBITDA and significantly increased cash flow,” he said, referring to earnings before interest, taxes, depreciation and amortization.

Yahoo's shares were little changed at $37.92 in trading after the bell.