Think you know everything about Bank of America (BAC -1.65%)? It's just a collection of industry-lagging and risky businesses, right? Dead wrong.

The surprising lead
At a recent conference, the head of corporate and investment banking at Bank of America, Christian Meisnner, gave a fascinating update on a little-discussed part of Bank of America that brought in $16.5 billion, or 18% of total revenue, for the bank last year.

One of the most enlightening revelations was a chart comparing the progress of the investment banking arm -- which represents the fees made from other businesses issuing stock, bonds, or buying other companies -- at Bank of America.

In 2013, Bank of America topped peers Citigroup (C -1.40%), Goldman Sachs (GS -1.36%) and others in a big way: 


Source: Company investor relations.

Even while most of the conversation surrounding Bank of America revolves around its more traditional banking arms, it turns out Bank of America was the nation's biggest investment bank last year -- ECM and DCM represent debt and equity capital markets deals, whereas M&A stands for mergers and acquisitions.

Not only did Bank of America lead the five other biggest banks in bringing in revenue through investment banking, but it trailed only Goldman Sachs in the growth of its business in 2013. This impressive lead wasn't simply in one area -- Bank of America said it held a top three position in seven of the eight industry groups that deals fall into.

Yet if you asked anyone what the biggest investment bank was in America last year, few would put Bank of America on the top of the list, and it may be a stretch for some to put it in the top five. Despite vastly overpaying for Merrill Lynch during the financial crisis, that acquisition is starting to bear fruit.

Why this matters to investors
Bank of America is still a commercial bank at its heart, it has nearly 50 million consumer and small-business relationships, versus "just" 5,200 corporate and investment banking clients, but its Wall Street-business is becoming more important.

Some detractors will say this exposes the bank to additional risk, but a Bank of America "bull" (myself included) would argue this diversity allows the bank to weather cyclical slowdowns in certain businesses like mortgage refinancing and fixed income trading.

After years of legal headaches, it's easy to forget Bank of America actually has a collection of successful business lines like its investment bank. The bank hasn't emerged from all its troubles yet, once it does, Bank of America's strongest businesses may (and should) get more attention from investors.