Given that you clicked on this article, it seems safe to assume you either own stock in M&T Bank (MTB 0.75%) or are considering buying shares in the near future. If so, then you've come to the right place. The table below reveals the nine most critical numbers that investors need to know about M&T Bank stock before deciding whether to buy, sell, or hold it.

But before getting to that, a brief introduction is in order. Established in 1856 as Manufacturers and Traders Bank, M&T Bank is today one of the 20 largest commercial banks in the United States. Headquartered in Buffalo, New York, it operates more than 700 branches and over 2,000 ATMs across eight states, the District of Columbia, and in Toronto, Canada. As of the end of 2012, it had $83 billion of assets on its balance sheet, ranking it in size between Alabama's Regions Financial and Texas' Comerica.

As you can see in the table above, from a shareholder's perspective, M&T Bank exhibits a number of attractive characteristics. Its net interest margin is above average, as are its return on equity and payout ratio. In addition, both of its non-performing loans ratio and its efficiency ratio are lower than average, evidencing a well-run bank that manages credit risk more effectively than its peers. It accordingly follows that the biggest downside is its valuation. Trading at 2.33 times tangible book value, M&T Bank stock is one of the most dearly priced regional lenders in the market today.

The one thing M&T Bank stock investors should be wary about is its recent acquisition of Hudson City Bancorp (NASDAQ: HCBK). To say that this is a transformative deal for M&T Bank is an understatement. With $40 billion in assets, Hudson City will increase M&T's size by 50% in one fell swoop. But while this sounds good in theory, acquisitions like this rarely work out for shareholders. A perfect example of this is First Niagara Financial's (NASDAQ: FNFG) recent transformative acquisition of HSBC's branch network in the Northeastern United States, which led the CEO of First Niagara to relinquish his post last month.