Clusia Acquires Optim ACH Solutions to Scale Fintech Regulatory Assurance

Clusia, a fintech assurance firm, has acquired Optim ACH Solutions and appointed Brian Stearns as Managing Director of Assurance Operations to scale its regulatory audit capabilities. For fintech professionals, this move signals a shift toward tech-enabled compliance, combining specialized ACH audit expertise with proprietary software to automate evidence gathering and streamline mandatory independent testing.

What was announced

Clusia has acquired Optim ACH Solutions, an ACH audit practice founded by Debbie Arai, for an undisclosed sum. The acquisition expands Clusia’s portfolio to serve more than 60 fintechs, third-party senders, and third-party service providers. Optim will continue its operations under the brand "Optim ACH, a Clusia company," ensuring that existing clients maintain their relationships with the current team while gaining access to Clusia’s technology stack. Debbie Arai, a veteran of payments risk management, joins Clusia as Managing Director, ACH Audits.

Alongside the acquisition, Clusia appointed Brian Stearns as Managing Director of Assurance Operations. Stearns joins the firm following a decade-long tenure at Wespay, where he most recently served as SVP, Supervisor of Risk Management Services. In his new role, he is tasked with leading improvements in audit delivery and overseeing the firm's expansion into broader assurance services. Clusia’s model focuses on regulatory audits and independent testing for money-movement companies, specifically targeting ACH audits and BSA/AML testing.

The firm utilizes proprietary software that connects to client systems or accepts uploaded documents to gather evidence automatically. This approach is designed to replace traditional manual methods, which typically involve gathering records from disconnected systems and completing lengthy questionnaires. By automating the data collection phase, Clusia’s auditors can test larger transaction samples than manual methods allow, focusing their professional judgment on investigating exceptions before signing final reports.

"AI is going to increase both the volume and complexity of work that requires independent assurance, and the firms doing that work today can only sell the hours they have,"

Reed Switzer

The companies involved

Clusia is an assurance firm dedicated to the financial technology and banking sectors, positioning itself as a technology-first alternative to traditional audit practices. The company pairs fintech operators and engineers specializing in cybersecurity and artificial intelligence with seasoned audit practitioners. This hybrid structure allows the firm to build its own software in-house, with engineers working directly alongside the auditors responsible for final reports. The firm’s strategy involves moving away from periodic, manual audits toward a model of continuous independent assurance, where evidence carries forward between engagements to reduce the recurring burden on clients.

Optim ACH Solutions is a specialized ACH audit practice that has established a reputation for payments risk management. Prior to its acquisition by Clusia, the firm operated as an independent practice providing audit work for a variety of financial institutions and third-party senders. The company maintains its own digital presence at oasnow.com. Under the new corporate structure, Optim will leverage Clusia’s technical infrastructure to enhance its existing audit methodologies. This integration is intended to transform periodic, manual audit processes into more consistent, software-supported engagements while retaining the specialized expertise of the original Optim team.

What this means

The acquisition of Optim ACH Solutions by Clusia highlights a growing friction in the fintech sector: the bottleneck of manual compliance. As transaction volumes and regulatory scrutiny increase, the traditional "billable hour" model of auditing is becoming a liability for fast-scaling firms. By integrating a specialized practice into a software-led platform, Clusia is challenging legacy audit firms that rely on manual sampling. This move puts pressure on traditional consultancies to modernize their tech stacks or risk losing market share to platforms that can offer continuous, rather than periodic, assurance. The industry is clearly moving toward a reality where "compliance-as-code" is no longer optional for firms operating in high-stakes payment environments.