What kind of marketing is it when “a company works continuously with its large customers to help improve their performance”?

Partnership marketing basically aims at adding more and more value to the benefits derived by a customer.

Partnership Marketing!

Partnership Marketing for mutual benefits.

Partnership Marketing. This gives a comfortable space between you and your customer to open up issues and resolve mutually. This will act us a catalyst to get your company and products promoted by your customer. In a way, customer helps in marketing your products and increases visibility. As long as your customer exist you will exist.

It is called as Partnership marketing. The objective is for both companies to either develop a short term or long term association/collaboration with a focus on leveraging strengths, customer base, brand name, etc to meet their respective business goals.

Its a partnership marketing....we both all involved equally...

Customer interaction, feedback (end consumer) quick communication, customer meet , motivate, educate gradually develop company's vision and concern towards customer.