I had a brief look this morning at a couple of exhibits in the Twitter S-1, documents pertinent to Dick Costolo's employment as CEO.
Like Marissa Mayer's employment as CEO of Yahoo, and Sheryl Sandberg's as COO of Facebook, Costello's employment with Twitter is memorialized, not in an "employment agreement" per se, but instead in a letter agreement.
Conspicuously missing is a "good reason" defined term, commonly used in executive employment agreements to set up severance benefits in the event that an exec's authority is undermined or she is effectively pushed out without actually being fired. Mayer and Sandberg both have such express protections in their respective letters.
That said, Costolo is entitled to severance, per a plan that is referenced by the letter, if he is fired without cause.
The most striking thing about Costolo's letter is his cash salary: $14,000 annually.
This suggests that his real compensation takes the form of equity.
I should of course look at the compensation disclosure in the prospectus to see what those are and how they are valued. But my real curiosity is with the mechanics of the underlying agreements.
It's possible that other terms material to Costolo's authority are embedded in other docs I haven't uncovered.