Chatham Financial Deploys OpenAI Codex and GPT-5.6 in Capital Markets

OpenAI published a customer story on October 2, 2026 detailing how Chatham Financial, a firm that advises clients on complex capital markets decisions, is using OpenAI’s Codex coding tool and GPT-5.6 models to build internal and client-facing technology, including a trade validation application that Chatham said reduced review time from approximately 30 minutes to under 4 minutes in early measurement.

Chatham uses Codex to build internal and client-facing tools and GPT-5.6 to power AI features, work that spans employee-built applications, the Chatham Onyx capital markets operating system, and Process Zero, the firm’s reengineering consulting service. The OpenAI page lists ChatGPT, Codex, and its API as the products in use at the firm.

Matt Henry, Chatham’s chief executive officer, described the firm’s design approach in the story: “We are not approaching AI simply as a faster way to run every process. With OpenAI, we can start with the outcome we want, identify where judgment matters, and design the best way to deliver it using the capabilities now available.”

Process Zero and Trade Validation

Through Process Zero, Chatham reengineers workflows around outcomes. For each workflow, the firm identifies the minimum inputs and evidence required, determines where human judgment is essential, and decides how AI and AI-built tools should support the work.

Trade validation is an early example. Chatham’s Controls and Data Integrity team protects the accuracy of transaction data by validating that each system record reflects what the client authorized and what was executed. Using Codex, Chatham developed a trade validation application that gathers supporting transaction evidence, compares key terms, and flags discrepancies for review, and the firm is comparing the application’s results with those of experienced reviewers.

“In early measurement, the application reduced review from approximately 30 minutes to under 4 minutes. Just as important, we are validating its performance against real transactions and experienced reviewers before we expand automation. Ultimately, we will be able to produce easily auditable and more accurate results faster,” said Alex Nordlinger, co-head of Chatham’s AI Advisory practice.

Chatham plans to extend the application to additional trade types and to automate more of the workflow while maintaining appropriate controls and professional oversight.

Chatham Vibes and Chatham Onyx

Chatham’s employees use ChatGPT and Codex in research, analysis, drafting, software development, and other daily activities. Employees have also become builders through Chatham Vibes, an internal platform for creating applications tailored to their work. AI features inside Vibes applications run on GPT-5.6 Terra by default, with GPT-5.6 Sol available as an optional upgrade based on per-app configuration.

These applications increasingly support client-facing workflows. One helps teams review maturing-cap trades and prepare pricing workbooks and client communications, while others support producing fixed-income rate sheets, preparing hedging dashboards, and reviewing trade confirmations. Chatham professionals evaluate the work, refine it where needed, and determine what reaches the client.

Chatham Onyx brings assets, debt, and derivatives into an environment where clients and advisors can work from connected, governed data and use AI without losing traceability to the underlying source. Chatham uses Codex across the Onyx development lifecycle to plan, build, test, document, and review software. Chief Technology Officer John DeGuenther said Codex is helping his teams turn product vision into working capabilities more quickly while the firm’s standards for accuracy, security, and accountability remain the same.

The Onyx platform uses GPT-5.6 Sol, GPT-5.6 Terra, GPT-5.4, and GPT-4.1, routing simple analysis and non-production testing to the most cost-effective models and reserving GPT-5.6 for complex tasks. One Onyx feature, ChatFIN, summarizes patterns in historical market data, helps users understand their portfolios, and locates and links to legal documents for debt, derivative, and lease terms. Chatham’s U.S. market rates page separately offers free sign-up for ONYX Pro, which provides access to historical rates and downloadable forward curves.

Chatham is also using OpenAI to perform structured comparisons, organize evidence, identify exceptions, and help teams explore information more efficiently. Mike Noonan, Chatham’s co-chief operating officer, said the firm’s constraint has been the hours its experts spend getting to the point where they can apply their expertise, rather than the expertise itself. Chatham’s stated next steps are expanding trade validation across additional products, continuing to refine employee-built applications, and using Codex to develop new Onyx capabilities.