Yahoo's back in the headlines again, with harsh criticism from yet another activist investor who doesn't like how the company's being run.

In a 99-slide presentation sent to Yahoo's board and published by Business Insider, Eric Jackson  of the SpringOwl investment firm claimed that Mayer spent $7 million on a Gatsby-esque "Roaring '20s"-themed holiday party this year. He points to the bash as an example of the way he believes chief executive Marissa Mayer had mishandled the company's money.  A source familiar with the company disputes that figure, saying that the 4,000-attendee party really cost one-third of that price — roughly $2 million.

A price tag in the millions, plus the theme of the party, has raised some eyebrows. Sure, Yahoo is celebrating its 20th anniversary and may want to celebrate with the exuberance of the Roaring '20s. But the 1920s also stand out for what followed, gives the theme a somewhat ominous twist.

Tech companies, of course, are known for their big holiday blowouts: The venue where Yahoo held its party has played host to LinkedIn, Google and others. SFist reported that LinkedIn had its holiday party there this year, while Twitter opted to rent out another popular venue, AT&T Park (yes, where the Giants play.)

Yet even if it's largely in keeping with what the rest of the tech industry offers, the big gala seemed inappropriate to some while Yahoo and Mayer are under the microscope.

Jackson's criticism of the party spending capped off a scathing analysis of Mayer's budgeting overall during her tenure at the company, questioning what value has come out of the money that Mayer has spent on acquisitions. He estimates that Yahoo's spent $2.8 billion on companies since Mayer started as chief executive in 2012, and argues that the company hasn't proven there's been real value from any of them. He particularly pointed to Mayer's $1 billion purchase of Tumblr, comparing it unfavorably to Facebook's $1 billion Instagram buy.

Mismanagement, he argues, may be contributing to an executive exodus at Yahoo, further destabilizing the company's leadership.

Jackson also questioned Mayer's spending on the most Silicon Valley of perks: Free food. Tech companies use these kinds of perks to recruit and keep tech employees happy — a way to keep them from jumping ship in a very competitive market. But Jackson said it's gone too far, estimating that Yahoo has spent $450 million over four years on feeding its workers.

That figure, however, is also in dispute: The same source close to the company said that Jackson's estimates for the food budget are overblown by a factor of 10, and that the company's food budget has really been more around $45 million.

SpringOwl did not immediately respond to a request for comment.