A report that Verizon and Google will bid for Yahoo on Monday, when first round offers are due, sent investors into a tizzy this afternoon.

Yahoo shares spiked 4.3% to $37.25 following the Bloomberg story, but quickly retreated.

The financial news service says that Verizon — which paid $4.4 billion for AOL last year — might sweeten its bid by also offering to buy Yahoo’s 35.5% stake in Yahoo Japan, valued at $8.5 billion. Google would just want Yahoo’s core ad-supported businesses.

Time Inc. and private equity firms Bain and TPG reportedly are still considering an offer. Microsoft might join with another bidder. But AT&T and Comcast have opted to stay out.

Yahoo’s under pressure to change direction. In February, its board formed a Strategic Review Committee and hired financial and legal teams to “evaluate strategic alternatives for the company.” The stock price has appreciated nearly 35% since then.

That likely would evaporate, though, if there’s no deal.

Yahoo’s privately telling potential bidders that its revenues (not including traffic acquisition costs) could fall about 15% to $3.5 billion this year, with earnings before depreciation, taxes and amortization down 20% to $750 million, Re/code reports.

Activist investor group Starboard Value is ready to pounce. In late March it proposed an alternate slate of directors. Starboard Managing Member Jeffrey Smith says the investment firm is “extremely disappointed with Yahoo’s dismal financial performance, poor management execution, egregious compensation and hiring practices and the general lack of accountability and oversight by the Board.”

Others also have been disappointed in Yahoo’s performance since 2012 when it hired Marissa Mayer as CEO with an aim to revive its status as a Silicon Valley icon. She sought to beef up the company with deals including a $1 billion acquisition of Tumblr and $650 million for BrightRoll.

She also built media properties around brand-name talent including Katie Couric and former New York Times consumer electronics critic David Pogue. The company produced longform TV shows including Sin City Saints, Other Space and Season 6 of Community, but in October said it had to take a $42 million write-down on them.