# The economics of fashion seasons and open-to-buy
A buyer at a mid-sized apparel brand signs a purchase order in January for dresses that will not hit stores until August. The factory needs the commitment now to reserve fabric and production slots. The cash leaves the business over the spring. The revenue, if the styles sell, arrives in the fall. That gap, months of money out before a dollar comes in, is the central problem of running a fashion business.
This lesson builds an open-to-buy plan and shows why cash flow, not creativity, is the binding constraint of a seasonal business.
Fashion sells in seasons: broad selling periods (Spring/Summer and Fall/Winter are the classic two, though most brands now run four to six micro-seasons). Each season has a rhythm:
The money problem: you commit to factory orders long before you know what customers actually want. Guess wrong and you either stock out (lost sales) or overstock (markdowns that destroy margin).
Open-to-buy (OTB) is a merchandise budgeting method that controls how much new inventory a buyer can commit to for a given period, based on planned sales, planned markdowns, and target ending inventory. Think of it as a cash and inventory governor.
The classic formula, in retail dollars, is:
OTB = Planned Sales
+ Planned Markdowns
+ Planned End-of-Month Inventory
- Planned Beginning-of-Month Inventory
- Merchandise Already on OrderIn plain terms: OTB is what you are still allowed to buy after accounting for what you plan to sell, what you will discount, the stock you want left at period end, the stock you already have, and the orders already committed.
If OTB is positive, you have room to place new orders. If it is zero or negative, you are fully committed and buying more just adds risk.
For a clear primer with worked examples, the Shopify guide to open-to-buy is a solid free resource.
Let us walk a single category (women's knit tops) through one month. All figures are illustrative.
Assume for August:
Apply the formula:
OTB = 200,000 + 20,000 + 150,000 - 180,000 - 60,000
OTB = $130,000 (at retail)So the buyer has $130,000 of retail value left to commit for August deliveries. If the brand's initial markup (the gap between cost and first ticketed price) means cost is roughly half of retail, that is about $65,000 of cash exposure for this one category, this one month.
Now multiply across dozens of categories and six drops. You can see how the buying budget becomes a company-wide cash forecast.
Here is what makes fashion harder than most retail. A large share of the season is pre-committed before selling begins.
Factories, especially overseas, require lead time. To secure capacity and raw materials, brands place bulk orders months ahead and often pay deposits. Once that purchase order is signed, it is largely locked. You cannot un-order it if trends shift.
This creates a structural squeeze:
Smart merchants leave a slice of the budget open, literally the "open" in open-to-buy, precisely so they can chase what is selling and skip what is not. A common practice is to pre-commit the reliable core (basics, replenishment items) and hold back budget for in-season reorders on proven winners.
Drops, releasing product in waves, change the cash math in useful ways.
One large shipment means one big cash outflow and a wall of inventory to sell through. Staggered drops spread both the buying commitment and the selling risk. If drop one sells poorly, you can trim or re-plan drop three.
This is why so many brands, from streetwear labels to mass retailers, moved toward frequent smaller releases. It is not only a marketing tactic to create urgency. It is a working capitalworking capitalWorking capital is the difference between a company's current assets and current liabilities, measuring short-term liquidity and the funds available to run daily operations.View full definition → strategy: releasing product in stages keeps less cash tied up in unsold goods at any one moment.
The trade-off: smaller orders often mean higher per-unit costs (you lose volume discounts) and more complex logistics.
Carryover is inventory that does not sell in its season and rolls into the next period. In fashion, carryover is expensive for three reasons:
1. Markdown risk: seasonal and trend-driven product loses value fast. What did not sell at full price in Fall often clears at deep discount later.
2. Cash locked up: money sitting in unsold stock is money you cannot use to buy next season's winners.
3. Storage and handling: warehousing costs accrue while the goods wait.
This is where the OTB target for end-of-month (or end-of-season) inventory matters. Set it too high and you plan yourself into carryover. Set it too low and you stock out and leave sales on the table.
A useful discipline: track weeks of supply (how many weeks current inventory would last at the current sales rate) and sell-through rate (percent of received units sold in a given window). When sell-through lags plan, cut future OTB before the carryover piles up.
Note that some categories, often called never-out-of-stock or core basics (a white tee, a classic jean), carry over intentionally and safely because demand is stable. The danger is fashion-forward, trend-dependent product carrying over.
Knowledge check
1. Why does the lesson argue that cash flow, not creativity, is the binding constraint of a seasonal fashion business?
2. A buyer commits to a large factory order long before the season begins. What is the fundamental risk this timing creates?
3. Open-to-buy is best described as which of the following?
4. Select ALL correct answers. According to the OTB formula, which factors INCREASE the amount a buyer is open to buy?
Select all the correct answers.
5. Select ALL correct answers. Which statements accurately reflect the economics of fashion seasons described in the lesson?
Select all the correct answers.
Step back and the pattern is clear. A fashion season is a bet placed months in advance, funded with cash that will not return until much later, and locked in by factory commitments you cannot easily reverse.
OTB is the tool that keeps the bet sized correctly. It forces a merchant to answer, before committing cash: How much do I really expect to sell? How much will I have to mark down? How much stock do I want left over? Everything else, drop timing, pre-commitment ratios, carryover targets, is a way of managing the timing and risk of cash.
A finance lens reframes the buyer's job. It is not "how many cute dresses can I order." It is "how do I deploy limited working capitalworking capitalWorking capital is the difference between a company's current assets and current liabilities, measuring short-term liquidity and the funds available to run daily operations.View full definition → across a calendar so that cash comes back faster than it goes out, at the best possible margin."
This is why fast-fashion and made-to-order models command so much attention. Shorter lead times shrink the gap between cash out and cash in. Smaller batches reduce carryover risk. Both loosen the working capitalworking capitalWorking capital is the difference between a company's current assets and current liabilities, measuring short-term liquidity and the funds available to run daily operations.View full definition → constraint that defines the industry. For deeper reading on inventory and cash cycles, McKinsey's State of Fashion reports (published annually and free) track how leading brands manage exactly these pressures.