Nathan’s experts guide clients on the development, negotiation, and resolution of virtually every type of long-tail insurance claim arising from historic CGL, specialty, and first-party property insurance policies.

Our experts and consultants have substantial expert witness credentials and can also provide a broad array of non-testifying consulting services.


Stephen E. Sellick  Nathan Associates

Stephen E. Sellick

Senior Vice President
+1 202 595 3566
Richard White

Richard White

Senior Vice President
+1 617 294 9737


Our experts provide analysis to clients pursuing or defending insurance coverage claims for environmental, mass tort, and other product liabilities. Our broad and deep experience includes allocation of past and future claims to insurance policies, incorporation of time value of money, alternative trigger and allocation theories, and unique policy details; assistance with insurance billing, including management of coverage-in-place agreements; compilation, verification, and reasonableness analysis of historic remediation costs; statistical analyses of claims databases to determine reliability for use in litigation; projection of future environmental and tort claims and costs using advanced modeling techniques; and the use of established sampling methods in litigation.

Allocation of Loss

Our experts can assist with claim management including complete claim administration and insurance billing, database design and implementation, quantitative reporting functions, and the development of complete strategic claim management frameworks. Our proprietary Claims Management System (CMS) is a fully customizable application that delivers a flexible and powerful integrated claims management solution. The CMS is designed, developed, and hosted internally, and ongoing claims management is handled efficiently by in-house personnel or outside counsel. All claims and lawsuit-related data and documents are managed in one place that provides secure and individualized access to all users. The system includes a suite of very powerful data export and reporting tools that include dashboard-style statistics, and graphing and reporting seamlessly integrated with other services, such as forecasting, allocation, and insurance billing.

Claims Management

Our experts can leverage their extensive experience in the analysis, verification, and management of historic cost claims to advise clients on ways of maximizing cost recovery through preemptive organization and maintenance of their cost management apparatus before initiating a claims process. Our work includes review and/or audit of existing accounting and cost tracking systems to ensure sufficient compliance with potential claim requirements; formulation of recommendations for internal documentation standards and recordkeeping practices to substantiate incurred costs; and, to balance both operational and strategic considerations, provision of guidance to client and contractor personnel responsible for those systems.

Cost Management Systems Optimization

Our experts combine economic, forensic accounting, and environmental response cost expertise to document and evaluate past environmental response costs. Our work includes accounting evaluation of invoices and internal costs, development of cost databases, and assessment of the reasonableness of environmental response costs. Cost reasonableness analyses include comparison of claimed costs against historical cost databases and other benchmarks.

Evaluation of Past Environmental Costs

Our experts—environmental professionals who have been actively involved in the environmental field since the inception of the U.S. EPA—have provided litigation consulting support and expert testimony on numerous cases in which corporate or governmental standard-of-care is at issue. Our experts have evaluated the historical practices of companies in virtually every industry and have provided detailed and authoritative assessments of whether these practices were within the standard-of-care and the company “expected or intended” to cause environmental harm with its practices. Our work in this area is supported by a large in-house library of historical environmental documents that allows our experts to place company practices in an appropriate historical context.

Expected & Intended Analysis

Claims presented for insurance coverage—whether at trial or in settlement discussions—often include issues relating to historical policy erosions. Our experts have experience reviewing loss runs and other evidence of policy erosions and determining their accuracy and reliability using established sampling methods to cost effectively present evidence at trial.

Historical Policy Erosion Review

Companies may be able to seek recovery from their historic insurance policies to help provide defense and indemnity coverage for claims they face. These policies can be a significant contingent asset, but, if an appreciable amount of time has passed, a policyholder may lack sufficient information about the policies to make a valid claim. Our experts conduct insurance archaeology research to identify and locate the policies or evidence of those policies. Our approach begins with the most cost-effective tasks and, as necessary, proceeds to include additional effort. Information sources include other policies, accounting and financial records, various archives, and employees. Our efforts often can locate policies or other evidence of coverage, which can place a policyholder in a stronger position to make use of the insurance asset.

Insurance Archeology

Our experts combine economic analysis with scientific, regulatory, and technical expertise to provide clients with multidimensional support on issues relating to environmental, tort, product liability, business interruption, property value diminution, and other claims. Our resources include advanced epidemiological models of asbestos disease, use of probabilistic modeling, and independent research into underlying data and trends.

Liability Estimation

Our experts have conducted samples to evaluate existing claimant and payment data and claims handling procedures for internal management and for litigation and settlement with insurance carriers and other parties that may share liability.

Statistical Analysis of Claims Data