OpEx (Operating Expenses)

Amazon & D2C glossary · Harpy Media

OpEx (Operating Expenses) covers the ongoing costs of running the business day to day: advertising, software subscriptions, warehousing, labour, third-party services, and the rent and admin of keeping the lights on. Where product development is spent once, OpEx is spent every month, forever.

What is OpEx?

OpEx (Operating Expenses) covers the ongoing costs of running the business day to day: advertising, software subscriptions, warehousing, labour, third-party services, and the rent and admin of keeping the lights on. Where product development is spent once, OpEx is spent every month, forever.

That repetition is what makes it dangerous. A one-off cost is a decision; a recurring cost is a decision made silently, every month, by not looking at it. Subscription creep, warehousing sized for ambitions rather than needs, and advertising that runs on default settings are how high-revenue brands end up with negative net profit while every individual line item looked reasonable when it started.

Why OpEx control predicts survival

Revenue can be bought; expenses have to be managed. A brand can double its top line and lose money if the running costs grow faster — and on a marketplace, they often do, because advertising scales with competition, storage charges scale with stock, and software scales with features nobody asked for. Strict control of recurring costs is therefore not frugality; it is the discipline that lets a profitable revenue level actually produce profit.

It also governs resilience. Every month of uncontrolled OpEx is a month of smaller buffers, and buffers are what absorb the marketplace’s shocks. Brands with lean operations survive a fee increase, a slow quarter, or a competitor’s price war; brands with heavy recurring costs that have quietly grown find that the same events become existential.

What belongs in the number, and how to keep it honest

The practical aggregation: advertising spend, fulfilment and platform fees, software subscriptions, warehouse rent or 3PL charges, and labour — separating operating costs from one-time product investment so the picture is comparable month to month. Run that total at a fixed cadence and hold it against revenue, so the ratio is visible rather than the absolute figure.

Then audit the components on a schedule. Every ninety days is a common rhythm for the software stack — overlapping tools, forgotten trials, and platforms that once solved a problem you no longer have. Warehousing should be matched to actual stock, not to the tier of business you hoped to be. And advertising should be reviewed continuously against margin, because it can grow to consume the gross profit while every dashboard still looks busy and healthy.

In practice

A seller launching a stainless steel water bottle audits their subscriptions and finds that only some of the tools in the stack are producing value. Cutting the redundancies and tuning PPC bids toward high-intent keywords reduces monthly overhead by around 15% — and the freed cash flow goes straight into a larger bulk order, which improves unit cost in turn. Nothing about the product changed; the operation around it got leaner.

How Harpy Media helps

Cost-stack discipline is part of our operating reviews with brands: subscriptions audited, warehousing matched to reality, and advertising held to contribution targets — so overhead stays proportionate as the catalogue grows.

OpEx FAQ

What counts as operating expenses on Amazon?

The costs of running the business: advertising, fulfilment and platform fees, software and subscriptions, warehouse rent or 3PL charges, labour, and general admin. They are distinguished from one-time product costs such as tooling or initial inventory purchase.

Why do operating expenses matter more than revenue?

Because recurring costs are the ones that decide whether revenue produces profit. High revenue with unchecked OpEx is the growth-bankruptcy pattern — impressive sales, thinning cash, and no buffer when the marketplace sends a shock.

How often should I audit my costs?

A quarterly audit of tools, subscriptions, and warehousing is a common and effective rhythm, with advertising reviewed continuously against margin. Recurring costs that are never audited tend to grow quietly, one reasonable decision at a time.