EY US and Watershed have formed an alliance to sell corporate emissions measurement and reporting as a combined service, the companies announced Monday. The offering pairs Watershed's AI-powered sustainability platform with EY's advisory, implementation and transformation practice in the United States.

The commercial logic is straightforward. Greenhouse gas accounting across operations and supply chains involves tangled data and contested methodologies, and a growing stack of disclosure rules now punishes firms that get it wrong. EY and Watershed intend to sell the untangling.

What does the alliance actually deliver?

The service covers the full chain of tasks, from data collection and emissions calculations to reporting, product carbon footprinting and sustainability planning. The companies list the concrete components:

• Greenhouse-gas accounting across Scope 1, 2 and 3 emissions
• Product carbon footprinting
• Automated, audit-ready sustainability reporting
• Decarbonization planning and emissions-reduction options

Watershed supplies the technology platform for managing climate and ESG data, generating reports and identifying reduction options. EY contributes sustainability advice, program management and implementation expertise.

Watershed's platform draws on a database of more than 3.2 million emissions factors, supported by in-house climate scientists and policy specialists. The company operates from London and San Francisco.

In plain terms: one partner owns the software, the other owns the consultants, and the client buys both at once.

Who is saying what?

Derek Przybylo, EY-Watershed Alliance leader at EY US, framed the partnership as a bridge from pledges to numbers. The alliance, he said, will help clients "turn sustainability objectives into measurable action through stronger emissions data and automated reporting."

Watershed Chief Executive Christian Anderson pointed to where the market is heading. Sustainability work, he said, is likely to become more automated and focused on action, with insights supporting operational efficiency and resilience as well as disclosure requirements.

That is a notable positioning choice. A few years ago, the pitch centered on disclosure alone. Now vendors sell carbon data as an operational tool, not merely a compliance artifact.

Why does this matter now?

The companies cite two pressures: regulatory requirements and expectations from customers and investors. Scope 3 emissions, which cover supply chains, remain the hardest category to measure and the one regulators increasingly ask about.

The alliance claims its output will be audit-ready — a word choice that matters. Sustainability disclosures are drifting toward the assurance standards that financial reporting already endures, and data that cannot survive an audit has a short shelf life.

The companies also say the combined services should make sustainability information more useful for operational decisions, not just for filings. Whether clients use the data to cut emissions or merely to fill forms will be the real test.

For Watershed, the deal extends its reach from software into large-scale consulting engagements; for EY, it adds a specialized platform to a service line under growing demand. Each side fills a gap the other could not close alone.

What comes next?

The alliance is a service offering, not a facility or a permit — no capacity figures apply. The metric that will decide its fortunes is adoption: how many of EY's US clients migrate their emissions accounting onto Watershed's platform, and whether audit-ready Scope 3 data becomes a purchasing criterion rather than a marketing phrase.

Watershed, meanwhile, has opened its 2026 carbon removal RFP round, and the SBTi has launched its Corporate Net-Zero Standard 2.0 with targets for carbon removals — both signals that the corporate carbon market is standardizing fast.

The next milestone is regulatory: as disclosure regimes tighten, measurement alliances like this one will either prove their worth in audit season or join the long list of sustainability partnerships that announced well and delivered quietly.