At times, banks can often be seen as complex institutions with entirely too much going on. While it's not very glamorous, one essential part of their business is their deposits. Yes, that boring line item on the balance sheet can tell a lot about both where a bank is going and where it's been.

It's important to remember that unlike every other company, to banks, deposits are liabilities, as they more often than not pay their customers to hold onto the customer's money. But they then use that money to lend to others (in the form of mortgages, businesses, and other loans) at a higher rate, and make their money off of the difference between the two, commonly known as the spread.

But these days, banks often have more deposits than they know what to do with, or even really need, and they have begun using the relationships they have with their depositors to sell them other products, such as credit cards, wealth management, or a whole host of other things. So while banks may not need deposits to fund new loans, they are still nonetheless enthusiastic about adding them to grow their market share.

With all of that in mind, let's dive into the deposits at five of the largest banks in the United States.

Bank

Deposits (in billions)

Bank of America (BAC -1.07%)

$1,147

Wells Fargo (WFC -1.11%)

$972

JPMorgan Chase (JPM 0.15%)

$952

Citigroup (C -1.09%)

$448

US Bancorp (USB -1.49%)

$235

Source: FDIC -- all data as of 6/30/13.

Bank of America: $1.1 trillion
Bank of America once again took the top spot in the deposit ranking, with over $1.1 trillion in deposits, as it grew its deposits 1.5% over the past year. Somewhat surprisingly, this growth in deposits came despite the bank closing almost 5% of its 5,660 branches that it had in 2012. Interestingly enough, despite it taking the lead in deposits, it actually has fewer branches (5,401) than both Wells Fargo (6,297) and JPMorgan (5,697).

Wells Fargo$927 billion
Wells Fargo added over $80 billion in deposits from 2012 to 2013, which represented a 9% gain year over year. As previously mentioned, it takes the lead in its total branch network, and it only reduced its total branch count by 19.

JPMorgan Chase: $952 billion
The biggest bank by assets at $2.4 trillion is actually the third biggest when you consider only deposits. Jamie Dimon's bank saw its deposits increase the most of the banks measured -- $87 billion (10.1%) year over year. JPMorgan was also one of the few banks to actually add branches, growing them by 89, or a little over 1.5%. In California and Florida alone it added 109 branches, but those states only accounted for $12 billion of its deposit growth.

Citigroup: $448 billion
Of the five banks, Citigroup was the biggest winner in its deposit growth rate, which stood at 13% as it added $51.5 billion in deposits. Interestingly this came despite the consolidation of 25 branches, or about 2.5% of its total from last year.

U.S. Bancorp: $235 billion
Finally we have Minneapolis-based U.S. Bancorp, whose deposits grew at 6.6% over the past year, or about $14 billion, as its total branch count remained flat, up a little more than 0.5%. It continued its strong dominance in the Midwest, as its deposits in Minnesota and Ohio grew by $8 and $4 billion, respectively.

In all of this, we see how five of the largest banks are adding to their foundational deposit base, and we can learn that despite branch consolidation, deposits are still rapidly growing at these banking behemoths.