Growing global advisory firm welcomes Managing Directors Nathan D. Fisher in San Francisco and Daron M. Hartvigsen in D.C.

Global advisory firm StoneTurn today announced the expansion of its Cybersecurity Practice with the addition of two senior-level cybersecurity experts: Nathan D. Fisher, a former Special Agent with the Federal Bureau of Investigation (FBI), has joined the firm as a Managing Director in San Francisco. Daron M. Hartvigsen, a former Special Agent in Charge of Cyber Investigations and Operations, Air Force Office of Special Investigations (AFOSI), has joined StoneTurn as a Managing Director in Washington, D.C. Nate and Daron will work closely with the firm’s Cybersecurity Practice Founding Partner Luke Tenery.

“Nation state-sponsored cyberattacks have increased significantly over the past few years, making it critical that the private sector leverages the sophisticated intelligence-gathering and counterintelligence tactics employed by federal agencies,” said Tenery. “With the addition of Nate and Daron, StoneTurn’s rapidly growing Cybersecurity Practice can leverage significant experience assembling technical, open source, and dark-web information to deliver actionable security insights for corporate and public-sector clients alike. Their intelligence expertise and incident response know-how will be a tremendous asset to StoneTurn clients seeking to protect their organizations from the increasingly profitable cybercrime economy. Furthermore, Daron and Nate solidify our national security and due diligence capabilities where cyber and human intelligence converge with transactional activity including mergers and acquisitions.”

During his nearly 12 years with the FBI, Nate worked on sensitive intelligence collection efforts, collaborating with several other U.S. intelligence community partners. A Russian speaker, Nate leveraged his language skills and subject matter expertise to support national security matters and inform policy. He also investigated threats posed by nation-state actors and worked with private sector and academic institutions to inform threat awareness and resolve vulnerabilities. At StoneTurn, Nate conducts a vast array of complex intelligence, counterintelligence, and cyber-focused investigations and operations. He also advises clients across the national security, Committee on Foreign Investment in the United States (CFIUS), and cyber spectrums.

A cyber threat response and mitigation expert with more than 25 years of experience, Daron has conducted incident response, cyber threat pursuit, law enforcement investigations, counterintelligence operations, intelligence analysis, and cyber threat degradation activities in the commercial sector. Prior to joining StoneTurn, Daron helped lead the build out of a new global consulting practice that routinely served the insurance and legal sectors with incident response, cyber investigations, cyber threat intelligence and expert witness services. Earlier in his career, Daron led global counter-threat investigations and operations as the Special Agent in Charge, Cyber Investigations and Operations Unit, at Andrews Air Force Base. His team received multiple awards from the Defense Intelligence Agency and the National Counterintelligence and Security Center for excellence in network traffic surveillance, cyber intelligence analytics, intrusion response, and sophisticated counterintelligence effects activities. Daron is a certified Digital Forensic Examiner, Computer Crime Investigator and Digital Media Collector.

Meet Nathan

StoneTurn Cybersecurity Managing Director Nathan (Nate) Fischer

Nathan D. Fisher

Nathan Fisher, a Managing Director with StoneTurn, brings over a decade of experience investigating national security threats to the U.S. government. As a Special Agent with the Federal Bureau of […]

Meet Daron


Daron Hartvigsen

Daron Hartvigsen, a Managing Director with StoneTurn, is a cyber threat response and pursuit expert that brings nearly 30 years of related experience in commercial, U.S. intelligence, counterintelligence, and law […]