Who are investors pushing for change at Yahoo?

In an increasingly public battle over how to steer Yahoo, activist investors have called out the company for everything from lavish holiday parties and Bon Appetit lunches to its acquisition strategy and a lit-up billboard off Interstate 80

But who are the investors behind such complaints?

Two of Yahoo’s most vocal investors, whose stakes in the company are large enough to pressure management, are Jeffrey Smith from Starboard Value LP and Eric Jackson from Spring-Owl Asset Management LLC.

Both are from East Coast firms and have made their mark in the corporate world by skewering executives through splashy slideshows. In Starboard’s case, the firm once creat--

ed enough skepticism that it caused the entire board of Darden Restaurants to be voted out by shareholders.

Once called “corporate raiders,” activist investors have “successfully rebranded themselves” as “defenders of shareholder value,” according to a report by J.P. Morgan last year. The amount of money managed by activist funds has increased from less than $12 billion in 2003 to more than $112 billion in 2014, the report said, largely due to their successful campaigns and more investors wanting to fund them.

“They have essentially positioned themselves not as the big bad wolves that are out there just to take care of themselves,” said Marc Zenner, cohead of J.P. Morgan’s corporate finance advisory.

And yet, despite their increasing popularity, it’s unclear whether activist investors do companies any good in the long term.

“The record is less clear as to whether they increase lasting value,” said Joseph Fuller, a professor of management practice at the Harvard Business School.

Activist shareholders generally go after underperforming companies. They buy significant stakes, and then can bring up any number of provocative issues, from breaking up a company to exploring a sale or pursuing a merger, J.P. Morgan’s report said. Many companies used to ignore activist investors unless they held at least 5 percent of the stock, the report said. Now, that’s no longer possible as bold investors — like those involved in Yahoo — can threaten to unhinge boards and generally succeed through expensive proxy fights.

Yahoo, which has received proxy threats from both Starboard and SpringOwl, has struggled to convince investors that it has a viable financial future. The stock has declined 38 percent in the last year, closing at $27.04 on Fri- day.

Already, the company has caved into some of Starboard’s demands, suspending a spin-off of its stake in Chinese ecommerce firm Alibaba and its small-business division amid investor concerns about tax liability; considering offers from buyers; and reducing its workforce. But still on the table is Marissa Mayer as Yahoo CEO, and whether members of her board will remain.

Although Starboard owns just 0.75 percent of Yahoo, it has been quite vocal in its criticism. SpringOwl has also been quite loud. In a 99-page slideshow in December, Jackson complained that “unnecessary Yahoo perks total half an Instagram,” and lamented the loss of Yahoo’s neon billboard.

“Go back to the old logo and raise the old Yahoo billboard ... into San Francisco to send a message that the era of Marissa Mayer is now over,” Jackson said.

By contrast, Yahoo co-founder David Filo

owns a 7.4 percent stake, but he has not spoken out publicly.

This isn’t the first time Jackson, a managing director at SpringOwl, has bothered Yahoo. When he was with another firm in 2007, Jackson waged a campaign to change Yahoo’s board and slammed then-CEO Terry Semel at its annual shareholders meeting.

“I am surprised you did not apologize to Yahoo shareholders for the last three years of performance,” Jackson told Semel at the meeting, according to a Chronicle report. Two days later, Semel resigned.

In Starboard’s current criticism of Yahoo, the hedge fund has yet to produce a public slideshow. But it didn’t hesitate to do so in 2014 when it unseated the entire Darden Restaurant board with a 249-page presentation. Starboard raised concerns about Darden’s overall strategy, but also slammed the company for little things, like placing five breadsticks at a table with four guests (wasteful, Starboard said) and using takeout containers that were dishwasher-safe. It

also called out the company for no longer salting the water for pasta, even citing a passage from the Frankies Spuntino cookbook.

“How does the largest Italian dining concept in the world not salt the water for pasta?” Starboard said in its slideshow.

Smith and Yahoo declined to comment for this article. Jackson was unavailable for an interview.

In the bigger picture, activist investors should be less concerned about pasta water and more about getting the best returns on their investments. One of Smith’s suggestions is that Yahoo sell its core business — in other words, its Internet properties and the tech giant’s lifeblood.

Investors have be- tween Feb. 25 and March 26 to file a slate of board candidates. J.P. Morgan says that activist investors land seats more than 45 percent of the time in a proxy battle.

One way that companies can fight back doesn’t necessarily involve a public relations battle. They simply need to run their companies well.

“There is no better defense against activism than share price outperformance,” the report said. “Underperformance weakens the current management team and gives the activist’s proposals a more friendly audience.”