DoorDash is buying Instacart: how to budget for a third retail media giant

For an emerging food, beverage, or household brand, retail media used to mean deciding how much to give Amazon and Walmart. A combined DoorDash and Instacart would add a third large buyer of your attention, and it would sit closer to the grocery aisle than either.

What was announced

According to the joint announcement, DoorDash will acquire Instacart for $65.00 per share, an equity value of about $17 billion, paid at least 75% in cash. Closing depends on Instacart stockholder approval, the Hart-Scott-Rodino antitrust waiting period, and other regulatory approvals including in Canada and Israel. Until then, the companies say they will operate as separate and independent companies, and after closing DoorDash expects to keep the Instacart brand, its enterprise technology products, and its app.

Three details in the release matter to a brand budget:

• The companies say brands "would gain a scaled alternative for reaching customers online."
• They say more grocers could use Instacart's technology to run their own websites and retail media networks.
• DoorDash committed to an open platform with no grocery exclusivity, so local grocers can keep working with any delivery platform they choose.

MediaPost reported that each company's ad business generates more than $1 billion in annualized advertising revenue, that Instacart's serves more than 7,000 brands, and that it is not yet clear how the combined company will handle targeting, buying, and measurement. Adweek reported that ad buyers expect the combined resources to be hard for brands to ignore, possibly second only to Amazon and Walmart.

Why this lands on the CMO and CFO desk

Retail media spend tends to grow quietly. A brand starts with a small test on one platform, the dashboard reports a strong return, the budget doubles, and a year later a large share of paid media depends on one company's auction, one company's reporting, and one company's rules. That is fine while the terms are good. It becomes a problem when the platform changes its fees, its formats, or its measurement, and the brand has no tested alternative.

A merger of two large grocery ad platforms raises that risk in both directions. A brand that spends heavily on both today may end up with most of its grocery delivery spend under one owner. A brand that spends on neither may find the combined platform is a door it cannot afford to ignore, with no history of its own to judge it by. Either way, the decisions are partly marketing and partly finance, which is why the CMO and CFO seats should make them together.

Set a ceiling for each parent company

Start by grouping your retail media spend by parent company rather than by app. After closing, DoorDash and Instacart spend would count as one owner. Then write down the largest share of total retail media spend you are willing to give any single owner, and the reason for that number. There is no correct figure for every brand; the point is that someone chose it on purpose and the team can see when it is crossed.

When a platform hits the ceiling, the next dollar goes to a test somewhere else, or it stays unspent until the evidence supports raising the limit. That rule protects you from a slow drift into dependence that nobody actually decided on.

Measure with tests you control

Every retail media platform reports its own return on ad spend, and every platform counts sales in ways that favor itself. Before the deal closes and reporting possibly changes, build a measurement baseline that does not rely on any one platform:

• Run holdout tests. Pause or withhold spend in a set of markets or retailers for a few weeks and compare sales to similar markets that kept running.
• Track total sales by retailer, not just attributed sales, so you can see whether ad spend grows the business or only claims sales you would have made anyway.
• Keep a monthly export of campaign results from each platform in a file you own, so a reporting change after closing does not erase your history.
• Agree on one return measure between marketing and finance, such as contribution margin after ad spend, and use it across every platform.

Fix the shelf before you buy the click

Paying to promote a product that is out of stock at the shopper's store is pure waste, and both companies have recently launched tools aimed at that problem. On September 23, 2026, DoorDash introduced Brand Center, which combines order data with shelf scans by its couriers to show on-shelf availability, out-of-stock trends, and estimated missed revenue. Its help page says Inventory Insights is available to eligible U.S. brands. On September 21, 2026, Instacart announced the Store Excellence Portal, a daily store-level view of the shelf for CPG brands, rolling out with select grocers and brands.

These are data tools, and access depends on eligibility, so confirm with each account team before you plan around them. Instacart also said on October 26, 2026 that it is winding down its Caper Cart business to focus on in-store software, so do not plan a budget around in-cart screen ads on its platform.

The practical order is simple. Check availability by retailer, fix the stores and products with gaps through your broker or distributor, and only then raise spend where the product is actually on the shelf.

Own your content and data

Platform dependence is not only about money. It is also about what you would lose if you left. Keep master copies of product titles, images, descriptions, and nutrition or ingredient details in your own files, and push them to each retailer and platform from there. Keep your sales and promotion history outside any ad console. If the combined company changes its catalog tools or reporting after closing, you can move without rebuilding from scratch.

What to watch before closing

• Regulatory steps. Watch for news on the antitrust review and stockholder vote, since a delay or a condition could change the timeline.
• Ad product announcements. Note any change to targeting, formats, minimum spend, or measurement on either platform.
• Grocer partners. Ask your grocers whether they plan to run their own retail media network on Instacart's technology, since that could add another place to buy.
• Contract dates. List any annual commitments with either platform and when they renew, so you are not locked in when terms change.

What to do this quarter

• Group retail media spend by parent company and treat DoorDash and Instacart as one owner in your plan.
• Write a ceiling for the share of retail media spend any single owner can take, and name who approves going over it.
• Run at least one holdout test on each platform you fund, and agree with finance on one return measure.
• Check shelf availability before raising spend, and ask each account team whether you qualify for its inventory data.
• Export campaign results monthly and keep product content in files you own.
• Review the split every quarter until the deal closes, and again after.

Questions brands ask about the DoorDash and Instacart deal