H&R Block is suing Block, Inc. over its name change from Square, alleging trademark infringement.

Square made headlines when it changed its name to Block in early December. The company chose the name to emphasize its broader strategy, with each of its various businesses serving as the building blocks of the company.

H&R Block is not a fan of Square’s move, calling the name change trademark infringement and accusing Square of trying to profit off of H&R Block’s brand.

Through many decades of hard work by its franchisees and associates, and billions of dollars invested in marketing, Block has built a valuable brand that has earned and maintained the trust and loyalty of millions of consumers. Rather than generating its own brand equity, Block, Inc. appears to be taking a shortcut to capitalize on the well-known Block moniker. This is a clear violation of Block’s trademark rights, which threatens to confuse consumers and cause harm.

“Today’s filing is an important effort to prevent consumer confusion and ensure a competitor cannot leverage the reputation and trust we have built over more than six decades,” said Jeff Jones, H&R Block President and CEO. “Protecting and defending our brand is crucial.”

H&R Block says it is already seeing indications that customers are linking the two companies, as a result of Square’s choice.