A spokesman for Wells Fargo declined to comment and Sard Verbinnen, which represents the board, did not immediately respond to requests for comment.

Andrew Duberstein at public relations firm Sard Verbinnen, which is representing the board, did not respond to requests for comment on the letter.

George Sard, the chairman and chief executive of Sard Verbinnen, said, “It was a great school, and I learned the business from him.”