Freshii Founder and CEO Matthew Corrin thinks Subway has expanded too far, too fast, and he wants to solve his rival's problem by converting some of its weakest stores to Freshii outlets.

"Let's explore a partnership in which we together convert select Subway stores to Freshii restaurants in a quick, low-cost way," Corrin wrote in his “Dear Subway” open letter published on Freshii’s website.

Corrin added "respected industry analysts" think Subway, which has 44,000 restaurants around the world, has expanded too aggressively.

He pegs the conversion cost for each location at around US$75,000. 

"Will this work? We know it will. We’ve already helped dozens of franchise partners from many iconic restaurant brands become successful Freshii partners by either converting their stores or bringing the Freshii brand into their portfolio."