Too Much Inventory, Still Out of Best Sellers

Your inventory report shows more stock than you have ever held, and three of your best sellers have been unavailable since last week. That combination looks like two contradictory problems. It is one problem, described twice: the money went into the wrong products, and the products it should have gone into ran out.

If the issue is a single fast-moving product whose own planning numbers have gone stale, that is a different diagnosis with a different fix, and it is covered in why best sellers keep going out of stock. This post is about where the cash across the whole catalog ended up.

One problem, not two

Every purchase order is an allocation decision. You have a finite amount of money to convert into stock, and the order decides which products it becomes. Do that a few dozen times without ever standing back to look at the resulting distribution, and the distribution is whatever the individual decisions happened to add up to. Nobody chose it.

Two symptoms follow from a distribution skewed toward slow products. The total inventory value rises, because slow stock accumulates rather than cycling out. Cover on the fast products thins, because the money that would have deepened them is already sitting in the first group. Treating those as separate problems produces the standard response of cutting the total while leaving the shape untouched, which shortens the fast products further.

The general causes of a stock pile getting larger than intended are covered in preventing overstocking on Shopify. The distinct question here is not why the total grew. It is why the total grew in one part of the catalog while another part was starving.

Why the total hides it

Aggregate inventory numbers are averages, and an average is the wrong instrument for a distribution problem. Here is what that means arithmetically, using one example store rather than any claim about a typical one.

Say the store holds $48,000 of stock at cost across 160 SKUs, and sells $4,000 of stock at cost each week. Split the catalog by revenue contribution over the last 90 days, which is the ABC half of grading every SKU on revenue and demand variability: the top 10 SKUs produce 60% of it, the next 40 produce 30%, and the remaining 110 produce 10%. Now look at where the $48,000 actually sits.

Convert each group's stock value into weeks of cover and the picture stops being abstract. The top 10 SKUs sell $2,400 of stock at cost per week against $9,600 held: four weeks of cover. The middle group sells $1,200 against $14,400 held: twelve weeks. The tail sells $400 against $24,000 held: sixty weeks.

The blended figure for the whole catalog is $48,000 divided by $4,000, which is twelve weeks. It matches the middle group exactly and describes neither of the other two. Read on its own it looks like a reasonably stocked store. Underneath it, four weeks of cover on the products carrying 60% of revenue is thin: a fortnight of lead time plus a review cycle eats most of it, and one strong week eats the rest.

That is the whole mechanism. A single aggregate cannot show a distribution, so the imbalance is invisible in exactly the report most stores look at.

How cash ends up in the wrong SKUs

Four routes, none of which require anyone to make an obviously bad call.

Reordering is triggered by scarcity, so abundance is never questioned. Every replenishment process fires on products running low. A product with sixty weeks of cover never crosses any threshold, never appears in a low-stock filter, and never comes up for review. It was bought at least once, and nothing in a reorder-driven process ever asks whether that was a good idea. Finding those products takes a deliberate query rather than an alert; identifying slow-moving inventory covers which metrics actually flag them.

New products are ordered against no history. Every SKU added to the catalog is a purchase made on a guess, and most catalogs add products faster than they retire them. A store that launches a handful of products a quarter and formally discontinues almost none will accumulate a tail whether or not any individual launch was reasonable, because the launches are decisions and the accumulation is not.

The fast products get trimmed last, so they get trimmed most. When the budget for a cycle is fixed, the tail's reorders and the new launches are usually committed first, because they arrive as small separate decisions across the month. The fast movers are ordered in one large line at the end, and that is the line cut to fit what is left. Nobody decides to under-buy the best seller; it is just the only order with enough slack to absorb the shortfall.

Review attention is spread by SKU count, not by importance. The tail holds most of the products, so it absorbs most of the review time available, while the ten SKUs that generate most of the revenue get the same few minutes each as everything else. Tiering that attention deliberately is the subject of prioritizing products for reordering.

The MOQ and price-break trap

Supplier minimums deserve their own section because their effect is regressive: the same rule forces the largest relative over-buy onto the slowest products.

Take a supplier with a 100-unit minimum. On a product selling 300 units a month, 100 units is about ten days of cover: a rounding decision. On a product selling 2 units a month, the same 100 units is over four years of cover, and the money is gone for that entire period. The minimum did not change. How long the stock takes to convert back into cash changed by a factor of roughly 150.

Price breaks work the same way and are harder to resist, because the saving is quantified and immediate while the cost is a slow product sitting on a shelf for two years. A quantity discount is only a saving if the extra units sell within a period you would have been willing to fund anyway.

The trap is not the minimum itself. It is applying the same acceptance rule at both ends of the catalog. For the fast group a minimum is a rounding step; for the slow group it is a decision to fund several years of stock, and it deserves to be treated as one: negotiate a smaller first order, split the minimum with another buyer, accept a higher unit cost for fewer units, or decline the product. Calculating how many units too many you are holding gives you the number to argue with.

Rebalancing without new cash

Rebalancing means changing the shape of the catalog's stock without increasing the total. Almost all of the room to move is in future orders rather than current stock, for the plain reason that money already spent on units in a box only comes back when those units sell, and the wider set of levers on that timing, supplier payment terms and order cadence among them, sits in reducing the cash tied up in inventory.

Set expectations honestly on the timescale. Freezing the tail changes the allocation of future spending within one cycle, but the stock already sitting in the tail leaves at the rate it sells, which on a sixty-week group is measured in seasons. Rebalancing is a direction, not an event.

The recurring cost of doing this properly is the arithmetic: recomputing per-SKU velocity, cover, and reorder quantities across the whole catalog often enough that the group split stays current. StockCue calculates those numbers per SKU from up to 24 months of order history and groups what needs buying by supplier, which is what makes a cover-based budget maintainable rather than a one-off spreadsheet exercise.

Frequently Asked Questions

How can you have too much inventory and still be out of stock?

Because inventory value is a total and availability is a per-product fact, and a total says nothing about how it is distributed. If most of the money sits in products that sell slowly, the total can be high while the handful of products that generate most of the revenue hold only a few weeks of cover each. The two symptoms are the same imbalance seen from opposite ends of the catalog.

What causes an inventory imbalance?

Mostly repetition rather than any single decision. Reordering is triggered by products running low, so slow movers are rarely reviewed and the money spent on them never comes back out. New products are ordered against no sales history. Supplier minimums force the largest relative over-buy onto the slowest-selling items. And when the buying budget is fixed, whatever the tail has already absorbed is not available for the fast sellers.

How do you rebalance inventory without more cash?

Start with the orders you do not place. Freezing reorders on the slow tail for one full cycle frees budget without spending anything, and it is the only rebalancing lever that works immediately. After that, set a days-of-cover target per group rather than per order, decide which slow products you will stop reordering permanently, and redirect the released budget into the fast group. Cash already spent on stock you hold only comes back when that stock sells.

Does a high inventory turnover rate mean the mix is right?

No. Turnover is a blended ratio across the whole catalog, so a small number of fast products moving a lot of volume can hold the overall figure up while a large slow tail sits untouched underneath it. A healthy-looking blended number and a badly distributed catalog are entirely compatible. To see the mix you have to split the catalog into groups and calculate cover for each one separately.