NEW YORK ( TheStreet) -- Lawyers are circling the $4.1 billion all stock acquisition of Marshall & Ilsley ( MI) by BMO Financial Group's ( BMO - Get Report) arguing executives did not get the best price for shareholders.

Two law firms, Rigrodsky & Long and Kendall Law Group are looking at claims that the board of directors of Marshall & Ilsley Corporation may have breeched fiduciary duty by not properly shopping the bank.

However, many analysts, such as Andrew Marquardt of Evercore, believe that the M&I was adequately shopped. "We suspect little interest from other parties (particularly from domestic banks)," he wrote in a research note.

Gauthier Vincent Partner at Booz & Company agrees that the bank received adequate consideration and that the $4.1 billion all stock acquisition illustrates that the worst is over in U.S. bank valuations with banking sector are making a rebound.

"Valuations in the U.S. are still depressed, but recovering. The return on equity (ROE) compared to book is close to where we were prior to the crisis," said Vincent. "You are beginning to see banks trading up in terms of market and while ROEs are less than what they used to be, or they are recovering."

Vincent added that the price, which was done at a 34% premium, was, "reasonable" because the deal price was 0.98x tangible book value. The deal values Marshall & Ilsley at $7.75 a share, and the bank is trading at $6.83 on the New York Stock Exchange.

"Essentially we didn't have values for buyers to look at before in the US. Buyers have had to worry about their own share prices," said Vincent.

This is a good deal for BMO and that the bank is likely to find cost savings in operations in its overlap of Harris Bank, Vincent adds. He explains that it's unlikely that BMO will spin-off its M&I's wealth management business because Harris, "has a decent wealth management business, and I don't think they will sell it, at least anytime soon."

In addition Vincent says he thinks that other Canadian banks such as Royal Bank of Canada ( RY - Get Report) and Bank of NovaScotia ( BNS) are looking at U.S. banks right now.

"I would not be surprised if all five banks evaluating their options and looking soon I would think the larger U.S. banks would begin looking too," Vincent said.

--Written by Maria Woehr in New York.

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