Purchasing: Its role, goals, structure and negotiations

30/10/2026 •0•0

What purchasing teams do, why every real saved goes straight to the bottom line, how the purchasing cycle works, whether to centralize and how to negotiate with suppliers.

作者Leon

翻訳者Editorial

改訂者Editorial

Introduction

This lesson begins the second part of the course. So far, we have studied how much stock to replenish and when to do it (demand forecasting, economic order quantity, safety stock, and continuous and periodic review). Now we turn to who makes replenishment happen: the purchasing function.

Manufacturing products, running a railway, managing a school or hospital, and providing municipal services all depend, among other things, on effective management of supplies and services. Efficient operations require the right inputs to be available at the right time, in the right quantity, and at the required quality.

When an input is unavailable when needed, the costs can include idle machinery, delayed orders, and lost customers. At the same time, buying too much ties up money in inventory (see the lesson on inventory costs). A well-structured purchasing process reduces both waste and the costs of failing to meet requirements.

The purchasing function

Purchasing usually refers to sourcing materials and services and obtaining them for a company. But that definition is too narrow: it describes the act of buying, not the full scope of the function.

Purchasing involves much more. It requires planning and follow-through, decision-making, researching and selecting suppliers, order follow-up (tracking orders to ensure on-time delivery), and inspecting the quality and quantity of what arrives. It also requires coordination with the rest of the company:

the warehouse, which receives and stores materials;
inventory planning, which determines purchase quantities and delivery schedules;
finance, which authorizes and controls invoice payments;
production, engineering, and quality, which define what is needed and the specifications it must meet.

At the start of the Industrial Revolution, things were very different. Each new technology required a group of suppliers willing to make the components for a new product: companies wrote specifications for each part, then looked for someone who could manufacture it. This still happens when developing a new product, and purchasing plays a decisive role in supplier development. But it is different from routinely buying established items in a market with many suppliers.

Knowing when to buy is crucial. Purchasing professionals need a clear picture of the supplier market, including seasonal price changes, availability, supply shortages, exchange rates, and international trade. Several factors shape that strategy:

The economy is global: a political or logistical problem on the other side of the world can disrupt supplies here (the semiconductor shortage that halted carmakers worldwide in 2021 is a recent example).
Material costs are affected by the inventory levels a company chooses to maintain.
Purchase price is the responsibility most closely associated with purchasing, and buyers play a central role in judging whether a price is fair.
Tracking the prices of the raw materials used in a purchased product is essential to negotiation.
Purchasing plays an important role in developing new suppliers.

Why purchasing has such a big impact on profit

In many industries, externally purchased materials and services account for more than half the cost of a product. That means every real saved on purchases goes straight to profit. Here is an example using round numbers:

Item	Amount
Annual revenue	R$ 10.000.000
Purchases of materials and services (60%)	R$ 6.000.000
Net profit (5% of revenue)	R$ 500.000

If purchasing cuts spending by 2%, the saving is 0,02 × 6.000.000 = R$ 120.000, and profit rises from R$ 500 thousand to R$ 620 thousand: 24% more. To earn the same R$ 120 thousand through additional sales at a 5% net margin, the company would need to sell another 120.000 / 0,05 = R$ 2,4 million, an increase in sales of 24%.

This classic calculation, known as the profit leverage effect, overstates the case somewhat because it assumes every additional real in sales earns the same 5% margin. In practice, fixed costs do not rise with sales, so additional sales generate a higher return. Even so, the lesson holds: a small saving in purchasing can equal a substantial increase in sales.

A company has annual revenue of R$ 20 million, spends R$ 12 million on purchases, and earns a net profit of R$ 1 million. If purchasing cuts spending by 3%, by what percentage does profit increase?

Answer: 36% — the saving is 0,03 × 12 million = R$ 360 thousand, all of which adds to profit: 360 thousand / 1 million = 36%. The tempting answer is 3%, but the saving is calculated on the 12 million spent on purchases, not on profit.

Objectives of the purchasing function

The purchasing function covers acquisition planning, requesting quotes, evaluating bids, and contracting suppliers. These objectives often compete (the cheapest option is not always the fastest or the best quality), but they serve one purpose: ensuring that the materials and services a company needs come in the right quantity, at the right quality, at the right time, at the right price, and from the right source. In practice, that means:

buying efficiently to maximize the company's benefit while meeting ethical standards;
ensuring supplies arrive in the quantities and within the timeframes users need;
building and maintaining a supplier database that supports a reliable flow of materials (see the lesson on supplier registration and evaluation);
maintaining strong coordination within the company and with the supplier market;
establishing streamlined procedures to keep the entire process under control.

Managing purchases and managing supply

Purchasing activities fall into two broad areas:

Purchase management: handles the transaction. It selects suppliers from the database to approach, researches prices, evaluates offers, negotiates, and finalizes the contract or order.
Supply management: begins after the contract is signed and ensures its terms and deadlines are met. It maintains regular contact with suppliers, monitors their raw-material markets, and tries to spot problems early enough to resolve them.

The cost of purchased inputs has a major effect on the final product's cost, and a company is vulnerable if it uses unsuitable materials or faces an unreliable supply flow. A recall illustrates what can happen when the technical side of purchasing goes wrong: when a carmaker asks vehicle owners to bring their cars in to replace a defective part, the problem almost always stems from a purchased component that failed to meet specifications, and the carmaker bears the replacement cost.

The purchasing cycle

From an internal request through payment, each purchase follows a recurring cycle:

The stages of the purchasing cycle

Need: someone (inventory control, when stock reaches the reorder point, or another user) submits a purchase requisition.
Specifications and sources: the item description is checked (see the lesson on material classification and coding), and suppliers are selected from the database for quotes.
Quotes: several suppliers are asked to submit offers on the same terms.
Evaluation and negotiation: price, delivery time, payment terms, freight, and quality are compared, then terms are negotiated.
Order or contract: the purchase is formalized (the purchase order is the document that binds the parties).
Follow-up (follow-up): the order is tracked through delivery.
Receipt and inspection: the warehouse checks the quantity and quality against the order and invoice.
Payment and evaluation: finance pays the invoice, and purchasing records the supplier's performance to inform future decisions.

The cycle feeds back into itself: the assessment of each delivery helps determine which supplier to buy from next time.

The warehouse reports that an order of bearings, which the supplier confirmed for delivery on the 10th, has still not left the factory on the 8th. Which purchasing activity is responsible for acting now?

Answer: Supply management, through order follow-up — the order has already been placed, so the purchase stage is over. The task now is to follow up to secure on-time delivery or arrange a solution in advance. Requesting new quotes would make sense only if the supplier could no longer fulfill the order.

Organizational considerations

Each company's characteristics determine where purchasing sits in its structure. The volume and complexity of the work depend on the size of the company. Core responsibilities include:

requesting quotes and running competitive supplier selection processes (in the public sector, procurement tenders, covered in upcoming lessons);
evaluating prices and supply terms;
negotiating and finalizing contracts;
registering, qualifying, evaluating, and developing suppliers;
studying the supplier market;
developing materials and conducting value analysis;
recording purchases and prices paid;
maintaining the materials catalog.

In some organizations, purchasing also covers materials management, contract monitoring, and invoice checks to authorize payment.

The first question in structuring a purchasing department is how much responsibility and authority it should have. In most companies, the purchasing manager reports directly to senior management because purchases account for a large share of costs. Elsewhere, purchasing falls under administration and finance; in many industrial companies, it reports to the industrial or production director.

Centralized structure

In a centralized structure, a single department handles purchases, with buyers typically assigned by material category (one buys steel, another packaging, and another maintenance services).

Assigning each type of material to one buyer prevents two buyers at the same company from purchasing the same item from different suppliers on different terms, effectively competing with each other. It also allows the company to consolidate volumes and lets each buyer become a specialist in that material and its market. The advantages of centralization include:

better company-wide control;
economies of scale when negotiating high-volume contracts;
more efficient use of staff with a smaller team;
avoiding harmful competition among regional buyers and different prices for the same material.

Decentralized structure

A decentralized structure makes sense when a company's sites are far apart. Regional purchasing departments with their own authority can respond faster to local needs; distance makes it difficult for a central department to handle urgent requests well. The advantages of decentralization include:

greater autonomy for regional sites;
more flexibility and a better understanding of local issues, suppliers, transportation, and storage;
faster response to emergency purchases;
better management of each site's own needs.

Generally, the drawbacks of one approach are the strengths of the other: centralization sacrifices speed and local knowledge, while decentralization sacrifices bargaining power and control.

The hybrid model

In practice, most companies with multiple sites use a hybrid model: the central department handles high-value purchases and long-term supply contracts (steel, energy, and freight), while regional sites buy what they need urgently or locally, within authorized limits. One common arrangement today is for the central department to negotiate a framework agreement at a set price, with each site placing its own orders under that agreement. This combines the scale of centralization with the speed of local purchasing.

A supermarket chain with 40 stores in five states buys cleaning products (the same ones for every store) but also needs urgent refrigeration repairs at individual stores. What is the best purchasing arrangement?

Answer: Head office negotiates cleaning products, while stores arrange urgent repairs locally within set limits — a standardized, high-volume item benefits from the scale of central purchasing, while an urgent local service benefits from decentralized speed. Centralizing everything could leave a cold room out of action while the store waits for head office to decide.

Negotiation

“Negotiation is the process by which the parties involved move from initially divergent positions to a point where they can reach an agreement”

- GONÇALVES, Paulo

Because negotiation involves people, understanding human behavior matters, especially interpersonal skills. The process moves through several stages before an agreement is reached.

One strategy is to maintain a good relationship and avoid confrontation. The negotiator looks for ways to cooperate and treats the other side amicably. This works well in a long-term relationship, but it carries a risk: someone determined to avoid conflict at any cost may give up too much. Before sitting down to negotiate, you need to know your limits.

Limits, alternatives and the zone of possible agreement

Three concepts help prepare for any purchasing negotiation:

Best alternative to a negotiated agreement (known in English as BATNA, a term popularized by Fisher and Ury in Getting to Yes): what you will do if the negotiation fails. For a buyer, that usually means turning to another supplier or making the item in-house.
Reservation price (or limit): the least favorable price each side will accept. The buyer's is based on their best alternative; the seller's is based on their costs plus a minimum margin.
Zone of possible agreement (ZOPA): the range between those two limits. An agreement is possible only if that range exists.

For example, a buyer needs a part. The next-best supplier can deliver the same part for R$ 52, including shipping, so paying the first supplier more than R$ 52 makes no sense. The seller, meanwhile, will accept no less than R$ 46. The buyer opens at R$ 44 and the seller at R$ 58, but any agreement will fall between R$ 46 and R$ 52.

Zone of possible agreement (ZOPA) between the buyer's and seller's limits

This has two practical implications. First, improving your alternative—for example, by developing a second supplier—strengthens your position before negotiations even begin. That makes a list of qualified suppliers a negotiating tool. Second, if the seller's minimum exceeds the buyer's maximum, there is no zone of agreement. Continuing to negotiate is a waste of time; the buyer should use the alternative.

A buyer has an alternative supplier that charges R$ 30 per unit plus R$ 2 for shipping. The supplier they are negotiating with will accept no less than R$ 33 per unit, including shipping. What should the buyer do?

Answer: Use the alternative, because there is no zone of agreement—the buyer's limit is the alternative's total cost, 30 + 2 = R$ 32; the seller will not go below R$ 33. Since 33 is greater than 32, there is no ZOPA. The trap is to compare the price of 30 with 33 and forget shipping.

Basic preparation rules

Work out tactical alternatives before you begin: new information may require you to change strategy mid-conversation.
If a proposal catches you by surprise, it is better to pause and resume later, after you have had time to assess it.
Decide how meetings will be conducted: open or closed, formal or informal.
Plan the place and time. Even where people sit can make a difference.
If you are negotiating as a team, agree beforehand on each member's role and the signals you will use.
Understand the contractual implications and the limits of your authority: know what you can decide on your own and when you need approval from above.
Document the agreement formally and have meeting minutes signed by those present. Before closing, recap what was agreed at each stage.
Pay attention to body language: nonverbal behavior can show how the other side is responding.

Advice for the negotiation itself

Aim to persuade, not deceive.
Show mutual respect: most negotiating relationships continue, and you will likely negotiate with this person again.
Keep emotion out of the process.
Do not underestimate or overestimate the other side's competence, knowledge or intelligence.
Do not assume the other side wants the same things you do.
Make the mutual benefits of the position reached clear, and recap the gains as talks progress.
Do not treat negotiation as a debate to be won on points; explore differences constructively.
Resilience, a competitive spirit and firmness build credibility.
What you say, ask and answer affects the other side's behavior.
Do not rush an agreement: give the proposal time to mature.
Information is the driving force in negotiation: protect yours and learn what you can about the other side's.
Persistence and determination matter, even when the other side holds the power.

Exercises

Easy

1) What is the purchasing function? Why is it important to an organization?

2) What is the difference between procurement management and supply management?

3) A company has annual revenue of R$ 5 million, spends R$ 3 million on materials and services, and earns a net profit of R$ 250 mil. If purchasing reduces that spending by 4%, how much will the company save, and by what percentage will profit increase?

4) Put the stages of the purchasing cycle in order: order or contract; receipt and inspection; need (purchase requisition); quotation; payment and evaluation; specifications and supplier selection; follow-up; analysis and negotiation.

5) A buyer knows another supplier can deliver the same part for R$ 80, including shipping. The seller they are negotiating with will accept no less than R$ 72. What is the buyer's reservation price, and what is the zone of possible agreement?

Difficult

6) Give the advantages and disadvantages of centralized and decentralized purchasing departments. When is a hybrid model most appropriate?

7) What is a negotiation process? Explain the zone of possible agreement using your own numerical example.

8) A manufacturer has annual revenue of R$ 8 million, spends R$ 4,8 million on purchases and has a net margin of 5%.
a) If purchasing reduces that spending by 2,5%, what will the new profit be, and what is the percentage increase?
b) Assuming each additional real in sales earns the same 5% margin, how much additional revenue would the company need to generate the same gain?
c) Now assume, more realistically, that fixed costs do not rise with the additional sales and that each additional real in sales contributes R$ 0,20 in margin. How much additional revenue would be needed? What does this show about the leverage effect?

9) A company needs 1.000 parts. It has two alternatives: supplier A charges R$ 41,00 per part plus R$ 3.000,00 to ship the batch; supplier B charges R$ 43,00 per part, including shipping. The company is negotiating with a third supplier, C, whose seller will accept no less than R$ 42,50 per part, including shipping.
a) What is the buyer's reservation price in the negotiation with C?
b) Is there a zone of possible agreement? What is it?
c) If supplier B can no longer supply the parts, how does the buyer's position change?

10) A chain has three branches, each using 1.200 units a year of an item priced at R$ 20,00. Each branch currently buys separately; each order costs R$ 50,00 to place, and holding one unit in inventory costs R$ 3,00 a year. Headquarters proposes centralizing purchasing: one order for all three branches, delivered to a distribution center that supplies them. The supplier offers a 2% discount for the larger volume. Using economic order quantity (see the lesson on economic order quantity), calculate the annual savings from centralization in ordering and holding costs and from the discount. What cost does this calculation leave out?

Answers

1) Purchasing is the function that sources, obtains and ensures a company's supply of materials and services. It goes beyond placing orders: it includes planning, researching and selecting suppliers, negotiating, following up on orders, inspecting deliveries, and coordinating with the warehouse, inventory planning, finance, production and quality teams. Its importance has two sides: a missing production input can stop production and cost the company customers, while purchases often account for more than half a product's cost, so every real saved goes straight to profit.

2) Procurement management handles the purchase through to the contract: it selects suppliers to approach from the approved list, researches prices, evaluates offers, negotiates and places the order. Supply management begins once the contract is signed and ensures it is fulfilled: it maintains contact with the supplier, tracks deadlines and anticipates problems.

3) Savings = 0,04 × 3.000.000 = R$ 120.000. Because all of it adds to profit, the increase is 120.000 ÷ 250.000 = 0,48 = 48% (profit rises from R$ 250 mil to R$ 370 mil).

4) Need (purchase requisition) → specifications and supplier selection → quotation → analysis and negotiation → order or contract → follow-up → receipt and inspection → payment and evaluation.

5) The buyer's reservation price is the cost of their best alternative, R$ 80. The seller's is R$ 72. The zone of possible agreement runs from R$ 72 to R$ 80: any price in that range is better for both sides than no deal.

6) Centralization offers company-wide control, economies of scale, a smaller team and an end to competition among buyers within the same company. Its disadvantages are slower responses and less knowledge of local problems and suppliers. Decentralization offers autonomy, local knowledge and a quick response to emergencies, but reduces bargaining power, can produce different prices for the same item and makes oversight harder. A hybrid model is best suited to companies with several widely separated locations: headquarters negotiates standardized, high-value items (often under a framework agreement), while individual locations buy urgent or location-specific items within set limits.

7) Negotiation is the process through which parties move from initially different positions toward an agreement. The zone of possible agreement (ZOPA) is the range between their reservation prices. For example, a buyer can get a ream of paper from another supplier for R$ 30, so will pay no more than R$ 30. The seller's cost is R$ 24, and they want a minimum margin of R$ 2, so they will sell for no less than R$ 26. The ZOPA runs from R$ 26 to R$ 30. If the seller would accept only R$ 31, there would be no zone of agreement, and the buyer should use the alternative.

8) a) Current purchases = R$ 4,8 million; current profit = 0,05 × 8.000.000 = R$ 400.000. Savings = 0,025 × 4.800.000 = R$ 120.000. New profit = R$ 520.000, an increase of 120.000 ÷ 400.000 = 30%.
b) Additional sales = 120.000 ÷ 0,05 = R$ 2,4 million, or 2,4 ÷ 8 = 30% more sales.
c) Additional sales = 120.000 ÷ 0,20 = R$ 600.000, just 7,5% more sales. Calculating the leverage effect using the net margin overstates the sales effort needed because additional sales do not carry additional fixed costs. Even so, a 2,5% saving on purchases equals 7,5% growth in sales: the leverage is real, just smaller than the conventional calculation suggests.

9) a) Cost per part from alternative A = 41,00 + 3.000 ÷ 1.000 = R$ 44,00; from alternative B = R$ 43,00. B is the best alternative, so the buyer's reservation price is R$ 43,00.
b) Yes: from R$ 42,50 to R$ 43,00, a narrow range. A deal with C within that range saves at most 0,50 × 1.000 = R$ 500.
c) Without B, A becomes the best alternative at R$ 44,00, and the ZOPA widens to R$ 42,50 to R$ 44,00. The buyer is worse off: they would accept paying up to R$ 1,00 more per part. That is why keeping alternative suppliers on the approved list is a negotiating tool.

10) In each case, ordering plus holding costs at the economic order quantity are Q ÷ 2 × c_m + D ÷ Q × c_p.
Separate orders (each branch): EOQ = √(2 × 1.200 × 50 ÷ 3) = √40.000 = 200; cost = 100 × 3 + 6 × 50 = 300 + 300 = R$ 600 per branch, or R$ 1.800 across all three.
Centralized orders: D = 3.600; EOQ = √(2 × 3.600 × 50 ÷ 3) = √120.000 = 346,4; cost = 173,2 × 3 + 10,39 × 50 = 519,6 + 519,6 = R$ 1.039,23.
Annual savings on ordering and holding costs = 1.800 − 1.039,23 = R$ 760,77 per year (tripling demand raises costs by only √3 = 1,73 times).
Discount = 0,02 × 20 × 3.600 = R$ 1.440,00 per year.
Total savings ≈ R$ 2.200,77 per year. This calculation excludes the cost of transporting and handling materials from the distribution center to the branches, as well as the loss of flexibility at branch level. If internal transport costs exceed about R$ 2.200 per year, centralization is not worthwhile.

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