as if (one) owns the place
In a supremely confident way. The phrase sometimes indicates that the speaker is annoyed by such confidence. Ugh, the boss's son always walks through the office as if he owns the place. I want you to walk into that interview as if you own the place—no false modesty.
as if someone owns the place
If you say that someone does something as if they own the place you mean that they do it as though they are the most important person there or they think they can do whatever they want. He strode across the hotel lobby like he owned the place. Note: You can also say like someone owns the place with the same meaning. He struts around town like he owns the place. Note: This expression is used to show disapproval.
as if you own the place
in an overbearing or self-important manner. informal