A London-based think tank has brought legal action against the Cardano Foundation for allegedly terminating a 2017 agreement.

The Zug, Switzerland-based group supporting the blockchain and cryptocurrency project confirmed in a blog post Monday that Z/Yen had initiated legal proceedings against it.

“It is our obligation to inform the Cardano community of legal proceedings recently initiated by the Z/Yen Group Limited (UK) against the Cardano Foundation (Switzerland),” the foundation said.

The dispute revolves around a reported agreement between the two organizations that the foundation allegedly terminated or voided for reasons not disclosed in the blog post.

“The Cardano Foundation fully rejects the claims raised by the Z/Yen Group Limited,” the blog post reads, adding it would not provide any further information while proceedings were underway.

However, the agreement in question appears to be one made in December 2017, when the foundation partnered with Z/Yen’s Distributed Futures practice for collaborating on new research papers, as well as exploring potential applications for Cardano and its ADA cryptocurrency.

At the time, Michael Parsons, the foundation’s then-chairman and executive director, described the Z/Yen partnership as “extremely important.” He said the two organizations would work together on the ongoing development of new tools and functionalities that would help increase industry understanding of governance and regulatory issues.

In February 2018, the Cardano Foundation’s official Twitter account posted about an event run by “our research partner” Z/Yen, for exploring how quantum computing could be used for blockchain security. Later that year, Z/Yen announced plans to experiment with smart ledgers for administering pension schemes, which would be sponsored by the Cardano Foundation according to a press release.

Charles Hoskinson, founder and CEO of IOHK, a Cardano developer, said the lawsuit is a “commercial dispute” and a “leftover” from the former administration of the foundation. He added that none of Z/Yen’s research had been used in the Cardano protocol.

Z/Yen’s co-founder and executive chairman, Michael Mainelli ,told CoinDesk neither he or Z/Yen were able to comment on the legal case while it was undergoing judicial consideration.

Established in 1994, Z/Yen is a commercial think tank for research and development into the finance and technology sectors. It launched its Distributed Futures group in 2015.