Every individual, firm, copartnership, joint venture, trust, business trust, syndicate, association or corporation making more than two retail sales of tangible personal property during any 12-month period, including sales made in the capacity of assignee for the benefit of creditors, or receiver or trustee in bankruptcy, shall be considered a retailer within the provisions of this part in his or its individual, firm, copartnership, joint venture, trust, business trust, syndicate, associate or corporate capacity.