Wycombe Wanderers managing director Steve Hayes has joined the board of London Wasps Holdings (LWH) Ltd, and bought an 11.6% stake.
Wasps have groundshared at Wycombe's Adams Park home since 2002 and the two clubs are looking at the feasibility of building a new stadium in the area.
"The relationship we have with Wasps is now planned to evolve into a deeper long-term partnership," Hayes said.
"My being on the board will help ensure the two clubs' ambitions are aligned."
Adams Park currently has a capacity of 10,000.
Wasps vice-chairman John O'Connell added: "As current European champions and having won 10 trophies in the last 10 years, we are clearly going to soon outgrow the current capacity.
"We have been heartened by the support from the local community since we moved to Adams Park four seasons ago, and a new stadium with increased capacity, with Wycombe Wanderers, is our preferred option."