Data source: Chart by author.

The financial crisis was the best thing that ever happened to Wells Fargo (NYSE:WFC). By steering clear of the most toxic types of subprime mortgages before the crisis, the California-based bank was able to exploit the missteps of its less prescient competitors and surge ahead in the crisis' wake. Wells Fargo is now on the verge of surpassing Citigroup (NYSE:C) to become the nation's third-biggest bank by assets.

Wells Fargo more than doubled in size in one fell swoop in 2008, following its acquisition of Wachovia, which it picked up for a 70% discount to book value. To put that price into perspective, Bank of America (NYSE:BAC) paid a 43% premium to book value to acquire Merrill Lynch at almost the exact same point during the crisis.

With the exception of 2009, Wells Fargo has since increased the size of its balance sheet every year through a combination of organic growth and acquisitions. In the third quarter of this year, for instance, its core loan portfolio grew by $73.4 billion, or 9%, compared to the year-ago period, marking the 17th consecutive quarter of year-over-year loan growth. And over the last two quarters, Wells Fargo has announced three separate deals with General Electric (NYSE:GE) to acquire various multibillion-dollar pieces of the latter's GE Capital unit.

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Conversely, both Citigroup and Bank of America have had to retreat and retrench from the financial crisis. Citigroup wrote off a staggering $28 billion loss in 2009 alone. And Bank of America has absorbed an unprecedented $195 billion in crisis-related costs over the past seven and a half years. It should come as little surprise, in turn, that both of the banks have since been more focused on cleansing their balance sheets of toxic and noncore assets, as opposed to growing through the addition of new assets.

The net result is that Wells Fargo will soon surpass Citigroup to become the nation's third-biggest bank by assets. In fact, after Wells Fargo consolidates its latest $32 billion purchase from General Electric, which was announced last week and thus not reflected on Wells Fargo's third-quarter balance sheet, it could feasibly do so by the end of the first quarter of 2016. This is a remarkable achievement for a bank that went into the financial crisis as little more than a regional lender operating, for all intents and purposes, west of the Mississippi River.

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