Generally speaking, when the stock market is doing well, the big banks are among the winners. Strong financial times tend to mean there’s more money around to fund all that growth, and that tends to benefit those actors profiting from moving that money around. What’s more, a growing stock market means more money in the hands of the sorts of people interesting in putting that money to work. Also good for investments banks.

So it should come as no shock that the primary ETF tracking the financial sector, the SPDR Financial Select Sector ETF ($XLF), is among the ETFs that are most actively traded and beating the S&P 500 in 2013, up 30.96 percent to the S&P’s 26.81 percent. In fact, it’s not out of the question to consider the XLF as a slightly leveraged version of the SPDR S&P 500 ETF ($SPY) given that the financial sector’s fortunes tend to be so closely tied to the market as a whole (though, it’s not designed that way and one could certainly get into trouble treating it as such).

So what’s in the XLF, then? Given that traders and investors are moving it around with an average daily volume that exceed 35 million shares, it’s worth taking a closer look at this ETF, what’s in it, and what major factors are most likely to make it move.

Times are Good for XLF, Financial Stocks

It’s been a solid year for financial stocks. The financial sector derives the majority of its revenues from lending money, trading financial instruments, and acting as a broker to others looking to trade financial instruments. And two factors have been working in confluence to facilitate all of these activities: a growing economy and low interest rates.

Low interest rates help people borrow and lend more money, increasing the sort of activity that the financial sector banks on (pun intended) for its regular cash flow. A growing economy also means an environment where people are more comfortable borrowing.

And the two factors together is a situation that’s not entirely a common one. Typically speaking, the Fed will raise interest rates in a growing economy/bull market to control inflation. At the moment, though, interests rates are at zero, the Fed continues to effectively print money through its stimulus programs, and inflation continues to appear to remain in check. It’s a situation that clearly can’t last forever, but one that’s made for a particularly positive environment for the financial sector over the last year.

XLF Holdings

Like most SPDR ETFs, XLF is connected to an S&P index, in this case the S&P Financial Select Sector Index ($IXM). The index has 82 components, all members of the S&P 500 operating in the financial sector. Quickly parsing over the numbers, XLF has actually missed its target index by a half percent in 2013, a big enough difference to make note of (IXM is up 30.43 percent in 2013 to XLF’s 30.96 percent). Not that most investors will be griping much given that A) they’re both up over over 30 percent and B) XLF was on the right side of that difference.

XLF’s holdings are cap-weighted and generally reflect the same ownership ratios of IXM, making them largely academic. However, for those interested, the breakdown is pretty much what you would expect, with the big four banks making up four of the top five holdings, each with more than 6 percent of the portfolio: Wells Fargo (WFC) at 8.18 percent of holdings, JP Morgan & Chase (JPM) at 8.1 percent, Bank of America (BAC) with 6.41 percent, and Citigroup (C) with 6.01 percent. Rounding out the top five is Berkshire Hathaway ($BRK.A) with 8.06 percent of the portfolio.

There’s a big drop off after those top five holdings, which generally reflects the nature of the sector’s major players. American Express ($AXP) is the fund’s sixth largest holding with just 3.06 percent of the holdings. The biggest investment-only banks have smaller holdings, with Goldman Sachs (GS) at 2.68 percent of holdings and Morgan Stanley (MS) at 1.63 percent.

XLF’s Prospects in 2014?

No one can tell the future, obviously, but it seems a fairly safe bet that XLF will at least fail to have the sort of banner year in 2014 that it has in 2013. For starters, the strong run for equities as a whole would seem to be an unsustainable rate of growth, let alone the financial sector. It also seems a pretty safe bet that the Fed will decide to start tapering QE III and raising interest rates in the next few months (though, getting a precise answer to the question of when will probably remain a focus of everyone’s interest until it happens).

With these downward pressures potentially coming in the approaching months, it seems difficult to believe that XLF will be able to match the massive 30 percent return its managed in 2013. What’s more, some technical patterns could also indicate a sell-off is coming. A look at the stock chart would seem to show a rising wedge developing over the summer and steepening sharply in early October. This pattern would seem to also point towards a potential downward breakout coming early next year.

Of course, if the equities market defies its bears and continues with another year of rapid growth, it’s not hard to imagine that any downturn based on the taper would be temporary and XLF would continue growing. As always, there’s no real way of knowing for sure until it happens.