Inventory Is Cash in Boxes: 6 Rules for Deciding How Much Stock to Hold

In June 2022, Target told the market it would cancel orders and take aggressive markdowns to clear stock it had bought and could not sell. The company cut its second-quarter operating margin guidance to roughly 2%, down from the 5.3% it had forecast weeks earlier (Reuters). Three months later, Nike reported first-quarter inventories of $9.7 billion, up 44% year over year (Nike investor relations), and spent the following quarters discounting its way back to normal.

Neither company had a demand problem. Both had bought too much, too early, and the balance sheet made them pay for it in margin.

Inventory is the only asset on your balance sheet that quietly gets more expensive the longer you own it, and the only one your team will defend as prudence right up until the write-off.

Our group was founded in Azagra in 1890 and now runs eight active verticals, from wine and mineral water to real estate and electrical installations, selling into more than 75 countries. Some of that inventory is supposed to sit still for years. Most of it is not. Here are the six rules we use to tell the difference.

Rule 1: Count stock in days, not in money

Ask a manager how much stock they hold and you will get a number in euros or dollars. That number is useless on its own, because it moves when sales move and tells you nothing about whether the level is right.

Convert it into time. Divide your inventory by your cost of goods sold, multiply by 365, and you have days of inventory: how many days of trading you are holding on the shelf. The inverse is your turnover ratio. Investopedia notes that many businesses target 4 to 10 turns a year, with the right number varying widely by industry.

The arithmetic is unforgiving. Four turns a year means roughly 91 days of capital sitting in boxes; six turns cuts that to about 61 days. Thirty days of stock released is thirty days of your own money handed back to you, and it costs nothing to raise.

Do this per category, never for the business as a whole. A blended average hides the twelve months of dead stock behind the two weeks of your bestseller.

Rule 2: Charge the warehouse rent to the product that is sitting in it

Most companies treat holding stock as free because the warehouse is already paid for. It is not free. Estimates compiled by Oracle NetSuite put inventory carrying costs at 20% to 30% of inventory value per year, once you add storage, insurance, handling, shrinkage, obsolescence and the cost of the capital tied up.

Take that seriously for one minute. At 25%, a product you bought for 100 and sell twelve months later has cost you 25 in carrying charges before you count a single euro of the purchase. If your gross margin on that item is 30%, you have just worked a year to earn 5.

Once carrying cost is charged to the product rather than buried in overhead, half the arguments about buying in bulk resolve themselves. The 8% volume discount that requires eleven months of stock is not a discount. It is a loan you are making to your supplier at a rate you would never accept from a bank.

Rule 3: Not every product deserves the same availability

The 80/20 rule holds in almost every inventory I have ever looked at: a small minority of items generates the large majority of the movement. Classify accordingly, in three buckets.

• A items: the fast movers that carry the business. Hold them deep, never run out, review them weekly.
• B items: steady but unspectacular. Normal cover, monthly review.
• C items: the long tail. Order them to demand, accept longer lead times, and stop apologizing for it.

The mistake is applying one service-level target across the whole catalog. Promising 99% availability on a C item that sells four units a year requires stock that will still be there in a decade.

Availability is a promise you should make deliberately, product by product, because you are paying for it product by product.

Rule 4: Safety stock is a calculation about variability, not a comfort blanket

Every warehouse holds a buffer. Very few can explain how it was set. Ask, and the honest answer is usually that someone was burned by a stockout once and the number has never come down since.

Safety stock exists to absorb two things: variation in demand and variation in supplier lead time. If your supplier is reliable to the day, you need almost none, however volatile demand is, because you can react. If your supplier swings between three and nine weeks, you are paying for their inconsistency in your own working capital.

That reframes the conversation with the supplier. Instead of asking for a price cut, ask for a shorter and more reliable lead time. A supplier who moves from six weeks plus or minus three to four weeks plus or minus one has just given you a cash benefit that usually dwarfs the discount you were negotiating for.

Rule 5: Separate working stock from strategic stock, and never let one hide inside the other

In wine, some inventory is supposed to sit. A reserva ages in barrel and bottle because time is the product. Judging that stock by turnover would be like judging an orchard by how fast you cut it down.

That is strategic stock: inventory held deliberately, for a reason you can write on one line, with a defined release date. Vintage depth, a pre-season build for a business with a real seasonal peak, a safety buffer against a genuinely fragile supply chain.

Everything else is working stock, and working stock is judged on turns.

The danger is not holding strategic stock. It is letting ordinary slow-moving product be reclassified as strategic in a meeting, because that is how it stops being measured. Keep the two in separate reports, with the strategic list short, named, dated and signed off by one person.

Rule 6: Give every product a kill date before you buy it

Obsolete stock is never a surprise. It is a decision nobody made, repeatedly, for years.

Fix that at the moment of purchase. Every buying decision gets a review date and a rule: if this has not moved by month X, we discount it, rework it, bundle it or scrap it. Write the sequence down in that order, because it is the order that recovers the most cash. The practical playbook the specialists recommend is exactly this ladder, discount first, rework or recycle next, scrap last.

The reason to decide in advance is psychological, not financial. In the moment, nobody wants to be the person who marks down their own buying mistake. A product that has not moved in a year will not start moving because you believe in it, and every month you wait, the discount required to clear it grows.

Key Takeaways

• Measure inventory in days of cover, per category, not in a single money figure for the business.
• Carrying costs of 20% to 30% a year mean slow stock can consume the entire gross margin of the product.
• A volume discount that requires a year of stock is a loan to your supplier, not a saving.
• Classify with the 80/20 rule and set availability targets per class, because you pay for availability per class.
• Safety stock is driven by supplier lead-time variability; a shorter, more reliable lead time is often worth more than a price cut.
• Strategic stock is legitimate only when it is named, dated and reported separately from working stock.
• Set the discount-or-scrap rule when you buy, not when the write-off is already in the accounts.

Frequently Asked Questions

What is an acceptable inventory turnover ratio?

Many businesses target between 4 and 10 turns a year, though the right figure varies enormously by industry: fresh food turns dozens of times, heavy equipment or aged wine barely at all. The useful benchmark is not a universal number but your own trend and your direct competitors. Rising turns with stable service levels is almost always good news.

What is the 80/20 rule in inventory?

It is the observation that roughly 20% of your products generate around 80% of sales or movement. It matters because it justifies treating those items completely differently: deep stock, tight monitoring and high availability for the vital few, order-to-demand for the long tail. Managing every product identically overspends on the tail and underserves the top.

What is the typical annual carrying cost of inventory?

Industry estimates commonly put it at 20% to 30% of inventory value per year, with some sources quoting 15% to 25% depending on sector. It includes warehousing, insurance, handling, shrinkage, obsolescence and the opportunity cost of the capital. Calculate your own figure once; it changes how your team buys.

How do you get rid of excess inventory?

Work down a ladder in order of cash recovered: discount and promote first, then bundle it with fast movers, then rework or repurpose the goods, then sell to a liquidator, and only then scrap or donate. Move faster than feels comfortable, because carrying cost keeps accruing while you deliberate and the recoverable value falls with every month.

Does inventory count in net working capital?

Yes. Inventory is a current asset, so it sits inside net working capital alongside receivables and cash, minus current liabilities. That is precisely why cutting excess stock releases cash without any financing: you are converting an asset you cannot spend into one you can.

One thing to do this week

Pull a list of every product line that has not sold a unit in the last twelve months, with its book value. Do not analyze it. Just read the total at the bottom, and ask what that money would be doing if it were in the bank instead of on a pallet.

Explore the eight businesses inside Manzanos Enterprises, and for the decisions that sit next to this one, read how the cash conversion cycle unlocks cash you already have, the five tests before you kill a product line and the margin stack that decides your export price.