If we in increased or decreases the number of units in San Francisco by 0.1%, i.e. added added 400 units. How much would that affect price? We can then reaso

If we in increased or decreases the number of units in San Francisco by 0.1%, i.e. added added 400 units. How much would that affect price? We can then reason backwards on what's the minimum sized landlord that would benefit from artificially restricting supply.