Yahoo Inc. has given prospective buyers until April to present preliminary offers for some of its assets, the Wall Street Journal reported late Monday.

In letters to potential suitors, the troubled Internet company asked them what assets they were interested in, how they would finance such acquisitions and what terms would have to be met on their end, the newspaper said, quoting people familiar with the matter.

The paper said some buyers might be interested in Yahoo's core web business or parts of it, while others might bid for stakes in Alibaba or Yahoo Japan.

Yahoo CEO Marissa Mayer, who took over in 2012 with the mission of boosting growth, is in an increasingly difficult position as she has failed to show concrete progress.

Although Yahoo is one of the best-known names on the Internet and is used by around one billion people, it has fallen behind Google in Internet searches and has been steadily losing ground in online advertising.

While Mayer has injected some energy and glamour into the company, Yahoo's finances have failed to improve and its core operations are valued in the market as worthless, with the company's valuation propped up by its stakes in Alibaba and Yahoo Japan.

In February, Yahoo said it was cutting 15 percent of its workforce and narrowing its focus as it explores "strategic alternatives."

The announcement, coming with the release of a big quarterly loss, offered the first sign that Yahoo may be open to a sale or merger after years of struggling to regain its former glory.

The California company reported a loss of $4.43 billion in the final three months of last year, due mostly to lowering the value of its US, Canada, Europe, Latin America and Tumblr units.

The Journal said some 40 companies potentially interested in Yahoo have signed non-disclosure agreements in recent weeks but Yahoo wants to narrow the field.

Yahoo had no immediate comment to the Journal report.