But in reality the bonus and RSU's are a very significant portion of compensation. I know several people in their late 20's in SF with salaries around $150k but after adding RSU's and annual bonus and other oddities like recurring "signing bonuses" they pull in between $200k and $250k per year before taxes. Even if it's slightly variable it is still a big difference from the base salary. As an example of why this matters, my base salary is $20k more than a certain friend of mine but my employer doesn't do RSU's and has relatively low bonuses, so in the end my friend makes around $50k per year more than me, which equates to a significant lifestyle difference.