http://www.kenniffonline.com/profits-are-everything/

How can Costco make profit selling everything so cheap? Is it just from the membership dues?
We at costco don’t go over a 14% IMU, often times much lower.
We don’t make 100% of the profit from Membership dues, but a majority of it is. Sorry I do not have exact numbers.
Ms. EVERYTHING: YOUNG KANO & PROFITS