In March, Canadian Pacific and Kansas City Southern agreed to a merger that would have seen the former buy out the latter for $29 billion and create a new company titled Canadian Pacific Kansas City, with three headquarters: a global one in Calgary, Alberta; a U.S. one in Kansas City; and a shared Mexico one in Mexico City and Monterrey. However, Canadian National, the country's largest rail network, then offered Kansas City Southern a higher bid, of $33.7 billion.

Either merger needed approval from the Surface Transportation Board, a subsidiary of the U.S. Department of Transportation. Because Canadian National's bid was higher, the Surface Transportation Board ruled on the Canadian National-Kansas City Southern; in the Board's ruling, it said that the intended voting trust for that merger would fall afoul of industry regulations. As a result, Kansas City Southern went back to its original suitor, Canadian Pacific, which increased its bid to $31 billion.

The boards of the original companies had approved the original merger. What is left is approval from shareholders of both companies and from the Surface Transportation Board, which had already approved that merger's voting trust, which was different from the one in the Canadian National deal.