What does Anthropic walking away from a $6 billion acquisition tell founders about due diligence?

On September 8, 2026, Bloomberg reported that Anthropic had completed due diligence on Decart AI . and walked away from what would have been a $6 billion acquisition.

Decart had raised $450 million from Nvidia, Sequoia, Benchmark, and Radical Ventures. They were last valued at approximately $4 billion in May 2026. Anthropic had reportedly been the preferred buyer. And then, after full diligence, the answer was no.

This is one of the most instructive deal collapses of 2026, because it illustrates exactly what can go wrong in late-stage due diligence . even at companies with exceptional investors, serious backing, and a credible strategic rationale.

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What happened in the Decart-Anthropic deal?

Nobody has confirmed the specific issue Anthropic found. But based on public reporting and the deal's structure, the most plausible explanations are:

1. Technology didn't perform at scale. Decart's core product reduces the cost of running AI by making chips more efficient. If Anthropic's diligence team found that efficiency gains degraded at the model sizes Anthropic actually runs, the strategic rationale collapses. You're paying $6 billion for something that doesn't solve your problem.

2. Founder motivations appeared misaligned. Reports suggested Decart's founders preferred Anthropic partly because they'd receive Anthropic stock . which will be publicly traded after the company's expected October IPO. If a buyer suspects a founder is optimising for the exit rather than the mission, that creates cultural risk the acquirer isn't willing to accept.

3. Pre-IPO structural complexity. Anthropic is preparing to go public. Acquiring a company with complex investor relationships . including parties with geopolitical sensitivities . introduces disclosure obligations and headline risk that no CFO wants to manage six weeks before a listing.

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What this means for founders not raising at $6 billion

The failure modes that kill mega-deals kill smaller ones too, just with different specifics.

In $10M–$100M exits . the range most ExitBoard founders operate in . the common diligence killers are:

• Revenue recognition issues. Deferred revenue, multi-year contracts recognised upfront, or ARR inflated by one-time payments that won't recur.
• Customer concentration. One customer representing 25%+ of revenue is a risk flag. Anything over 30% will require a rep-and-warranty carve-out, or kill the deal.
• Key-man risk. If the buyer's team interviews your employees and discovers that three customers stay because of their relationship with you personally . not the product . that's a risk that reprices the deal.
• Contractual vulnerabilities. Assignment clauses that require customer consent to transfer in an acquisition. Change-of-control provisions that trigger option vesting. Terms you signed in 2021 that you forgot about.
• Tech debt and IP ownership. Open-source licensing issues. Engineers who wrote IP on contractor agreements with unclear assignment. Prior employer IP claims.

Buyers find all of these things. Their counsel is paid to find them.

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How to prepare for due diligence before you start a process

The single most effective thing a founder can do before running an M&A process is perform their own diligence first.

This means:

• Reviewing every customer contract for assignment, termination, and concentration risk
• Reconciling your ARR figure against actual contracted recurring revenue
• Identifying every key-man relationship in your customer base and having a transition plan
• Auditing your IP chain: employment agreements, contractor agreements, open-source usage
• Preparing clean, organised financial records that match your representations exactly

This is not a banker's job. Bankers optimise for starting the process and getting to LOI. They are not incentivised to surface problems that would slow down the deal or lower the price.

The preparation work happens before the banker is engaged.

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The Founder Clarity Session

At ExitBoard, the Founder Clarity Session is a 45-minute structured review designed to surface what a buyer will find before you start a process. We work through the same questions a buyer's M&A team will ask . revenue quality, customer concentration, key-man risk, IP chain, and timing signals.

Most founders come out of it with 2-3 things they need to fix before starting a process. Some come out knowing they're ready now. Either answer is more valuable than finding out in month four of diligence.

[Book a Founder Clarity Session →] (link to exitboard.ai/clarity)

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