The idea of "wire fraud" might seem like a rather obscure notion these days. Communicating via wire could evoke images of old-time telegraph operators or other outdated notions. However, the federal government defines wire fraud much more broadly. "Interstate wire communications" covers a lot of different areas, and wire fraud is a very serious crime indeed.
After massive fines, firings and more looming legal cases, it's certain that Wells Fargo won't be the only corporate example of the Department of Justice. Continuing a pattern of cutting the head off the snake, the DOJ issued a memo in 2015 that called for extensive corporate prosecutions.