Valve is a unique company with no traditional hierarchy. In business school, I read a very interesting Harvard Business Review article on the subject. Unfortunately it’s locked behind a paywall, but this is Google AI’s summary of the article which I confirm to be true from what I remember:

According to a Harvard Business Review article from 2013, Valve, the gaming company that created Half Life and Portal, has a unique organizational structure that includes a flat management system called "Flatland". This structure eliminates traditional hierarchies and bosses, allowing employees to choose their own projects and have autonomy. Other features of Valve's structure include: 

• Self-allocated time: Employees have complete control over how they allocate their time 
• No managers: There is no managerial oversight 
• Fluid structure: Desks have wheels so employees can easily move between teams, or "cabals" 
• Peer-based performance reviews: Employees evaluate each other's performance and stack rank them 
• Hiring: Valve has a unique hiring process that supports recruiting people with a variety of skills