Tariffs Are Rewriting the Due Diligence Playbook

Twenty percent of global CEOs told PwC's 2026 annual survey that they expect to be highly or extremely exposed to tariffs over the next 12 months. That single data point explains why deal teams across the middle market are rewriting their due diligence templates in real time. Supply chain resilience has moved from a second-order risk factor to a primary input into purchase price, and the mechanics now reach into MAC clauses, earnout triggers, working capital adjustments, and indemnification baskets. Any owner planning to sell, any buyer preparing to acquire, and any investor evaluating a current portfolio company in a tariff-exposed sector is now operating inside a changed contract template. Getting the mechanics right is what separates a clean deal from a post-close dispute.

What Changed in the Diligence Process

Five years ago, a due diligence scope on a manufacturing or consumer goods target typically treated tariff exposure as a line item inside quality of earnings. Buyers checked harmonized tariff codes, reviewed country-of-origin documentation, and normalized EBITDA for any one-time tariff events. The analysis fit on a page or two of a quality of earnings report.

That scope has expanded meaningfully. Diligence teams now build a full supply chain map covering first, second, and increasingly third-tier suppliers. They quantify tariff exposure under multiple rate scenarios. They test pricing power against each scenario, asking whether the target can pass through cost increases to customers without losing volume. They model the cash conversion cycle under a stressed tariff regime to understand working capital needs. And they document the target's contingency plans (alternate supplier qualification, inventory pre-build, contract price adjustment clauses) in enough detail to price them.

For export-heavy sectors, specifically automotive, industrial machinery, chemicals, and consumer electronics, this is now the heart of the diligence workstream rather than a sidebar. For domestic-facing businesses, the work is lighter but not absent, because most companies have upstream tariff exposure through inputs even when they do not export.

How the Contract Is Absorbing the Risk

The legal document has moved in lockstep with the diligence process. Three mechanisms have become common in middle-market transactions signed in the last 12 months.

The first is the tariff-specific material adverse change (MAC) clause. A traditional MAC is drafted to exclude general economic changes, industry-wide developments, and changes in law unless they are disproportionate to the target. Tariff-specific MACs either remove the general carve-out for changes in trade policy or define a specific dollar-threshold or operational-impact trigger that counts as material. The effect is to shift tariff risk between signing and closing back to the seller, at least partially, in a way traditional MACs typically did not.

The second is the expanded earnout. Earnouts have long been used to bridge valuation gaps where the buyer and seller disagree about forward performance. Tariff volatility has added a new use case: earnouts tied to cost pass-through success. If the target passes through tariff increases to customers without margin compression, the earnout pays out; if not, the downside is absorbed by the seller. This structure is especially common where the business has meaningful tariff exposure but the seller believes its pricing power is stronger than the buyer credits.

The third is working capital and inventory mechanics. Purchase price adjustments for working capital are standard in nearly every deal. Tariff inventory has introduced a question of valuation. Should pre-tariff inventory be valued at landed cost, replacement cost, or net realizable value? Deal teams are negotiating specific inventory valuation methodologies inside the working capital definition rather than defaulting to "consistent with the accounting policies historically applied."

What This Means for Sellers and Buyers

For a seller, the practical lesson is that tariff exposure is now a documented dialogue, not a background topic. Going to market in 2026 without a clean supply chain map, a tariff scenario model, and a credible pass-through narrative will not kill the deal, but it will compress the price. Conversely, a seller who arrives with that workstream already complete shifts the conversation from "how big is the risk" to "how much is the seller's preparation worth," which is a far better conversation to have.

For a buyer, the discipline is to treat the tariff diligence as part of the quality of earnings scope rather than as a sidebar. The same EBITDA number can be worth very different multiples depending on the underlying supply chain. A business doing $30 million of EBITDA with a diversified supplier base across multiple trade blocs is a different asset than a business doing the same EBITDA with 60 percent of its input cost concentrated in a single high-tariff jurisdiction, and the multiple should reflect that.

For an investor already holding a portfolio company, the question is whether the diligence work done at acquisition still stands up. Portfolio company CFOs are adding quarterly tariff exposure reviews to their management reporting, and sponsor operating partners are funding dual-sourcing and nearshoring initiatives that would have been rejected as unnecessary cost two years ago. The cost of those programs is rarely trivial, but the cost of discovering a concentrated exposure at the next financing or exit is higher.

Forward Look

Two dynamics will shape tariff-era diligence through the rest of 2026. The first is policy direction. The broad trade policy framework has been volatile enough that deal teams are assuming volatility as a baseline rather than a temporary state. That assumption will persist through any near-term policy changes because the underlying uncertainty is now priced into deal documents. The second is data infrastructure. More advisory firms are building their own tariff modeling toolkits, and more sellers are investing in enterprise resource planning (ERP) upgrades that allow them to produce tariff exposure reporting on demand. Over the next 12 to 18 months, sellers that can produce a credible tariff scenario model at the start of a process will look meaningfully better prepared than those that cannot, and that visibility difference is beginning to translate into a pricing difference.

In PwC's most pessimistic 2026 scenario, broader tariff escalation compresses total deal volume by roughly 3 percent. That level of compression would not destroy the market, but it would sharpen the bid for prepared sellers and widen the discount on unprepared ones. The practical response is the same in either direction: build the diligence workstream now, document the exposure clearly, and get the legal mechanics right before the LOI is signed.