The activist investor who emerged last month with a big stake in Buffalo Wild Wings Inc. on Wednesday urged the company's board to seek "fresh talent" and criticized the way executives spend money.

Richard "Mick" McGuire, founder of Marcato Capital Management, said in a letter to directors that the Golden Valley-based company's growth objectives have become muddled and that executives appear to be making decisions that aren't supported by data.

His portrayal of Buffalo Wild Wings poses a stark challenge to the reputation and perception of a company that for a decade has been one of the fastest-growing restaurant chains in the U.S. — and delivered enormous returns for shareholders. However, its sales growth faltered over the last year and customers criticized some of its price hikes.

In response, Buffalo Wild Wings issued a statement saying its executives, board members and outside investors have met with Marcato several times in recent weeks. "Our Board and management team will continue to engage constructively with Marcato, and we will also consider the input of our other shareholders," the company said.

Shares in Buffalo Wild Wings rose 3 percent as investors absorbed the exchange.

Marcato in late July revealed that it took a 5 percent stake in Buffalo Wild Wings and that it planned to suggest changes in management and the company's capital structure. The letter it publicized Wednesday came a day after executives told investors and analysts they would add $300 million to its stock buyback program.

The amount of that increase disappointed some investors, but McGuire raised a different objection in his letter, saying executives tend to "favor gut feel and thematic proclamations without tangible evidence or appropriate analytical support."

He said executives say they want Buffalo Wild Wings to be a "growth company," usually with a goal of per-share profit growth of 15 percent or more, but don't appear to be considering the costs of the methods they've identified to grow.

"Beneath the headline, there is no calculus as to how same-store sales, operating margin expansion, franchise vs. company unit growth, franchisee acquisitions, and share repurchases will combine to produce such a result," McGuire wrote.

He added, "Growth in revenue or earnings simply cannot be evaluated without consideration for the capital deployed in the achievement. This basic principle of corporate finance is tragically underappreciated by the current management team."

McGuire was not specific on who he would like to see replaced, but he wrote, "The company must improve its experience and sophistication in areas of restaurant operations, franchise system development, corporate finance, and capital markets."

McGuire said he believes strongly in the concept of Buffalo Wild Wings' core restaurants, which attract people to watch sports on big-screen TVs. He added there may be room in the U.S. and Canada for more than the 1,700 restaurants that Buffalo Wild Wings thinks it can build. It now has just under 1,200 locations worldwide.

Evan Ramstad • 612-673-4241