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Supply Chain Contracts. Gabriela Contreras Wendy O’Donnell April 8, 2005. Outline. Introducing Contracts Example: ski jackets Buy-back Revenue-sharing Quantity-flexibility Newsvendor Problem Wholesale Buy-back Revenue-sharing Quantity-flexibility
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Supply Chain Contracts Gabriela Contreras Wendy O’Donnell April 8, 2005
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems and open questions
A contract provides the parameters within which a retailer places orders and the supplier fulfills them.
Example: Music store • Supplier’s cost c=$1.00/unit • Supplier’s revenue w=$4.00/unit • Retail price p=$10.00/unit • Retailer’s service level CSL*=0.5
Question What is the highest service level both the supplier and retailer can hope to achieve?
Example: Music store (continued) • Supplier’s cost c=$1.00/unit • Supplier’s revenue w=$4.00/unit • Retail price p=$10.00/unit • Supplier & retailer’s service level CSL*=0.9
Characteristics of an Effective Contract: • Replacement of traditional strategies • No room for improvement • Risk sharing • Flexibility • Ease of implementation
Why? Sharing risk increase in order quantity increases supply chain profit
Types of Contracts: • Wholesale price contracts • Buyback contracts • Revenue-sharing contracts • Quantity flexibility contracts
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems & open questions
Example: Ski Jacket Supplier • Supplier cost c = $10/unit • Supplier revenue w = $100/unit • Retail price p = $200/unit • Assume: • Demand is normal(m=1000,s=300) • No salvage value
Formulas for General Case • E[retailer profit] = • E[supplier profit] = q(w-c) • E[supply chain profit] = E[retailer profit] + E[supplier profit]
Results: Optimal order quantity for retailer = 1,000 Retail profit = $76,063 Supplier profit = $90,000 Total supply chain profit = $166,063 Loss on unsold jackets: • For retailer = $100/unit • For supply chain = $10/unit
Optimal Quantities for Supply Chain: • When we use cost = $10/unit, supply chain makes $190/unit • Optimal order quantity for retailer = 1,493 • Supply chain profit = $183,812 • Difference in supply chain profits = $17,749
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Buy-Back Contracts Supplier agrees to buy back all unsold goods for agreed upon price $b/unit
Change in Formulas: • E[retailer profit] = • E[supplier profit] = q(w-c) 3. E[overstock] = + bE[overstock] – bE[overstock]
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Revenue-sharing Contracts Seller agrees to reduce the wholesale price and shares a fraction f of the revenue
Change in formulas • E[supplier profit]= (w-c)q+fp(q-E[overstock]) • E[retailer profit]= (1-f)p(q-E[overstock])+vE[overstock]-wq
Expected results from revenue-sharing contracts for ski example
“Go Away Happy” “Guaranteed to be There”
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Quantity-flexibility Contracts • Retailer can change order quantity after observing demand • Supplier agrees to a full refund of dq units
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Contracts and the Newsvendor Problem • One supplier, one retailer • Game description: Y Accept Contract? Q N Production End Product Delivery Demand Recognition Transfer payments
Assumptions • Risk neutral • Full information • Forced compliance
Profit Equations pr = pS(q) – T ps = T – cq P(q) = pS(q) – cq = pr +ps p= price per unit sold S(q)= expected sales c= production cost Proof:
Transfer Payment What the retailer pays the supplier after demand is recognized T = wq w = what the supplier charges the retailer per unit purchased
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Newsvendor Problem Wholesale Price Contract Decide on q, w
Let w be what the supplier charges the retailer per unit purchased Tw(q,w)=wq
Retailer’s profit function pr= pS(q)-T
Supplier’s Profit Function ps= (w-c)q
Results: • Commonly used • Does not coordinate the supply chain • Simpler to administer
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Buy-back Contracts • Decide on q,w,b • Transfer payment T = wq – bI(q) = wq – b(q – S(q))
Claim A contract coordinates retailer’s and supplier’s action when each firm’s profit with the contract equals a constant fraction of the supply chain profit. i.e. a Nash equilibrium is a profit sharing contract
Buy-back contracts coordinate if w & b are chosen such that:
Recall: pr = pS(q) – T pr = pS(q) – wq – b(q – S(q)) = (p – b)S(q) – (w – b)q = lP(q)
Recall: ps = T - cq ps = – cq wq – b(q – S(q)) = bS(q) + (w – b)q – cq = (1 - l)P(q)
Results Since q0 maximizes p(q), q0 is the optimal quantity for both pr and ps And both players receive a fraction of the supply chain profit
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems
Newsvendor Problem Revenue-Sharing Contracts Decide on q, w, f
Transfer Payment Tr= wq + pS(q) (1-f)
Retailer’s Profit pr= pS(q)- T • For l Є (0,1], let fp= lp w= lc pr= lP(q) f
Similar to Buy-Back From Previous Slide: pr(q,wr,f)=lP(q) Recall from Buy-Back: pr(q,wr,b)=lP(q)
Outline • Introducing Contracts • Example: ski jackets • Buy-back • Revenue-sharing • Quantity-flexibility • Newsvendor Problem • Wholesale • Buy-back • Revenue-sharing • Quantity-flexibility • Results for other problems