Third Point's 5.1% stake preceded Mayer's hiring; Yahoo shares rose 67%

On September 8, 2011 Third Point disclosed a 5.1% stake in Yahoo and sent the board a letter blaming failed deals and governance for destroyed value, calling the company's churn of CEOs a symptom of weak leadership.

Under pressure, Yahoo's board ran a CEO search and on April 16, 2012 named Marissa Mayer president and CEO, effective July 17, 2012, an outside hire after a string of internal and interim leaders.

Mayer refocused Yahoo on products, buybacks and the Alibaba stake. By May 7, 2013 the stock had surged 67% since her arrival, and by September 2013 it had nearly doubled, with much of the gain tied to Alibaba.

Yahoo hired Marissa Mayer as CEO in July 2012; shares nearly doubled by September 2013, helped by Alibaba.

The 13D and letter put the board's failures on record before any vote.

A 5.1% position made Third Point one of Yahoo's largest outside shareholders, giving the letter force.

The board chose a visible outside CEO rather than fight the campaign.

Buybacks and Alibaba's rising value gave the turnaround numbers to show.

An activist can force a leadership reset without a proxy fight: Loeb's letter and 5.1% stake raised the cost of inaction, and the board answered with an outside CEO and a strategic focus.

Loeb left Yahoo's board in July 2013 with a large profit. Alibaba later drove most of Yahoo's remaining value, and the company was sold to Verizon in 2017; the campaign became the textbook case of an activist changing leadership without a proxy contest.