While working at a company, be loyal to your local team (other people just trying to do good work) and yourself (e.g. build new skills you can use). And really, those are variations of the same thing because co-workers that value you can help you get what you want or even your next job.

Blind loyalty to a company means nothing though. First, managers change: any promise, especially a long-term one, is one manager-change away from becoming vapor. Projects are cancelled or relocated or reprioritized. Layoffs occur at times convenient for the company so don’t be surprised when you’re unable to count on stock vesting. Perks go away. Ultimately, treat most company-level things as “sounds nice” and never count on them. For example, I would never buy a house based on stock I should get or a bonus that was promised.