Should a DTC Brand Set Ad Spend by Inventory and Margin?

A DTC brand should set ad spend by inventory and margin, because a revenue target treats a product with 70% margin and one with 25% margin as equally good, and keeps buying clicks for products that are about to sell out. This is CB/I Digital's point of view, and the reasoning rests on how the ad platforms bid and on simple margin arithmetic.

This report explains why revenue-based bidding misallocates spend, what the platforms already offer to fix it, and a weekly routine for running budgets by margin and stock. Platform details are as of 25 October 2026.

Should ad spend follow inventory and margin?

Ad spend should follow inventory and margin, because platform bidding chases the conversion value it is given and ignores what each sale is worth to the business or whether the product can be shipped.

Google's target ROAS bidding aims for the average conversion value you'd like to get for each dollar you spend, and for most stores that value is revenue. A $100 sale of a product with a 70% margin and a $100 sale of one with a 25% margin look the same to the bidding system.

The arithmetic shows why that matters. Shopify gives breakeven ROAS as one divided by gross profit margin. At a 40% margin a product breaks even at 2.5x, and at 25% it needs 4.0x. A blended 3x target loses money on every product with a 25% margin, which needs 4x, while products with a 40% margin could take more spend.

Why spend on low-stock products wastes money twice

Advertising a product that is nearly sold out spends money on demand the brand cannot fill, and can also reach shoppers who would have bought it anyway.

When stock runs short, clicks on that product either end in an out-of-stock page or bring orders the brand would have taken without ads. When the product is marked down, ads drive sales at a margin that may sit below breakeven. Both cases show up as respectable ROAS in the platform report.

The scale of the inventory problem is large across retail. IHL Group's 2026 research, as reported by Retail Insider, puts the cost of stockouts and overstocks at about $1.7 trillion a year, equal to 6.2% of global retail sales, with two-thirds from out-of-stocks. That figure covers mostly store-based global retail, so read it as context rather than a DTC benchmark.

What Google and Meta already offer

The platforms have the controls, and most brands use only part of them.

Google. Merchant Center supports custom labels that the help page itself suggests for margin, clearance, season or selling rate, and Performance Max and Shopping campaigns can bid on those groups. Conversions with cart data, combined with the cost of goods sold attribute in the feed, let Google Ads report gross profit by product. Google has also offered bidding toward profit in Performance Max and Shopping as a beta, and says users saw an average 15% uplift in campaign profit against revenue-only bidding, from its own 2023 Shopping data. Treat that as Google's claim and test it with a holdout. It needs cart-data conversions and the cost attribute in the feed, which Merchant Center describes as for reporting purposes, and one agency estimated in 2024 that only about 5% of advertisers had both in place.

Meta. Meta's documentation for Advantage+ catalog ads says products marked out of stock in the catalog automatically stop serving, and that fetching the catalog often keeps stock information current. Serving stops only after Meta receives the updated feed.

Shopify Catalog also feeds ChatGPT and Merchant Center feeds Google AI Mode, so stale stock data reaches AI shopping answers too. Neither platform reads a brand's margins or reorder plans by itself. They act on the labels and stock data in the feed, so the feed has to change as often as the stockroom does.

A weekly routine for spend by margin and stock

Running budgets by margin and stock means repeating the same checks every week.

1. Set breakeven ROAS by margin tier. Group products into three or four margin bands and calculate breakeven for each, using margin before ad spend after product cost, shipping, packaging and payment fees.
2. Label the feed. Put margin band, stock status and markdown status into custom labels in Merchant Center and the Meta catalog, and refresh them at least as often as stock changes meaningfully.
3. Check cover before raising spend. In Shopify, look at days of inventory remaining for advertised products, and pull back spend on any hero product with only a few weeks of cover until stock arrives.
4. Push budget to in-stock, full-margin products. Give the high-margin, well-stocked groups the higher budgets or lower ROAS targets, and the low-margin or clearance groups targets above their breakeven.
5. Check the business result. Read contribution margin after ad spend, marketing efficiency ratio and the share of spend on low-stock products each week, not platform ROAS alone.

Common Thread Collective's Q1 2026 data across 299 DTC brands found brands with a higher marketing efficiency ratio had a higher median contribution margin, a correlation that supports managing to margin rather than revenue. Breakeven by margin is explained step by step in what is a good ROAS for a DTC brand, and inventory cover sits on the scorecard in which metrics a DTC brand should review every week.

What gets in the way

The barriers are mostly data and habit rather than platform features.

Cost data is often scattered across spreadsheets and finance systems, so margin by product is not in the feed. Stock changes in Shopify with every order, but feeds refresh on a schedule. And marketing teams are usually measured on revenue or ROAS, which rewards the blended approach this report argues against. Changing the team's measure to contribution margin after ads gives it a reason to follow the routine.

Frequently asked questions

Does Google Ads bid on profit?

Google has offered profit optimization for Performance Max and Shopping as a beta that uses cart data and cost of goods sold. Check whether it is available to your account, and test it against revenue bidding.

What if our cost data is not accurate?

Start with margin bands rather than exact costs. Grouping products into three or four tiers already separates the products that lose money on ads from those that do not.

Should we stop advertising products that are low in stock?

Pull back rather than stop, and resume when stock arrives. A product with a few days of cover cannot absorb more demand, while a product with months of cover can.