Wiss and Rillet Partner to Deliver a New Accounting Model for Growing Businesses

Co-sourced model pairs Rillet’s AI-powered platform with Wiss’s accounting and advisory services to give high-growth businesses a more scalable, efficient way to manage finances

FLORHAM PARK, N.J.—June 26, 2025—Wiss, a full-service accounting and business advisory firm leveraging AI and data analytics to deliver advanced financial solutions, and Rillet, the AI-native enterprise resource planning (ERP) platform, today announced a strategic partnership aimed at helping businesses streamline operations, improve financial visibility, and reduce reliance on manual or outdated processes. For businesses navigating the challenges of rapid growth, this new offering provides both the tools and the talent needed to scale with confidence.

With this new partnership, businesses gain access to a co-sourced accounting model that blends technology and expert advisory services. Rillet’s software automates core accounting tasks such as invoicing, monthly closes, and financial reporting, while Wiss provides outsourced accounting support, financial reporting expertise, and tailored strategic advisory. This integrated approach enables businesses to move beyond basic bookkeeping and operate with the kind of financial clarity and control typically associated with larger enterprises. 

“Our partnership with Rillet illustrates the direction that Wiss is heading as a modern accounting and advisory firm focused on delivering actionable and strategic insights that go beyond just numbers,” said Paul Peterson, CEO of Wiss. “We’re continually seeking out forward-thinking solutions that break the mold of traditional accounting and reflect a more modern, technology-enabled way of supporting our clients.”

Additional benefits of this collaboration include:

• Shorter close cycles and stronger reporting: Automated workflows and clean data structures streamline monthly closes and reduce time spent on manual reporting.
• Built-in scale and flexibility: Businesses get access to enterprise-grade technology and finance expertise without the overhead of building it all in-house.
• One unified experience: A fully integrated model where software, services, and strategic guidance work seamlessly together, eliminating the gaps and inefficiencies that come from juggling multiple vendors or platforms.

“Rather than offering traditional outsourcing, Wiss has embraced a co-sourced model that pairs strategic guidance with day-to-day execution,” said Jim Duffy, President of Wiss. “By integrating Rillet’s technology into this model, we’re able to give clients real-time visibility into their financials while significantly reducing the manual work behind the scenes. It’s a more modern, efficient way to support businesses as they grow and face more complex financial demands.”

“Wiss is a firm that’s truly thinking ahead when it comes to modern finance,” said Nicolas Kopp, CEO of Rillet. “They share our belief that companies deserve better tools and better guidance. This partnership is about delivering both, so finance leaders can spend less time compiling numbers and more time acting on them.”

This partnership builds on Wiss’s successful collaboration with Basis AI, which automated core accounting workflows and freed teams to focus more on strategic support. The Rillet partnership represents a natural next step in Wiss’s mission to modernize the accounting experience through technology-driven approaches and deliver deeper, more strategic value to clients.

About Wiss

Headquartered in Florham Park, NJ, and with offices in New York City and Florida, Wiss is clearing the path for a new era of accounting. We bring technical experts powered with AI to meet the needs of today’s data centric, growth-minded customer. Wiss is an accounting business that goes beyond the numbers, offering our dynamic clients a full spectrum of accounting and advisory services. Every Wiss client is engaged with a tailored team of specialists who advise on specific needs at their stage of growth. Wiss taps into the full potential of what an accounting business should be—modernizing the experience for clients, teams, and the industry at large. For more information on Wiss, go to wiss.com.

About Rillet

Rillet is the AI-native accounting platform made to tailor fit the workflows of accountants and a full replacement for legacy ERPs. Scaling and hyper-growth companies like BitWarden, Windsurf and Postscript use Rillet to enable a smarter close with native integrations, automated journal entries and AI embedded workflows.  They are backed by Sequoia, First Round Capital and Creandum with offices in New York and Barcelona.

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