Follow the money -- the "smart money," that is.

Pro investors have been buying stocks again in 2016, but they've been selective with where they put their money. Only five of the S&P 500's 15 sector categories saw an increase in positions from last quarter, signaling that while the pros still like stocks right now, they don't like all stocks. And this summer, the stocks that the pros are buying can tell you a lot about the stocks you might want to think about for your own portfolio.

Think of it like an investing shortcut. By leaving the hard analysis to the pros, you get all the perks of a well-staffed equity research department, without paying the hefty management fees found at the world's most successful hedge funds.

And believe it or not, you don't have to guess to figure out what the funds are buying right now. In fact, they'll tell you.

That's because institutional investors with more than $100 million in assets are required to file a 13F, a form that breaks down their stock positions for public consumption. From hedge funds to mutual funds to insurance companies, any professional investors who manage more than that $100 million watermark are required to submit a form 13F to the SEC.

Want to know which stocks are pro investors' favorites? Those 13F filings hold the key.

By comparing one quarter's filing with another, we can see how any single fund manager is moving their portfolio around. And by looking at those changes collectively, we can see which stocks the pros are betting on as a group. In other words, we can see which stocks Wall Street loves. While the data is generally delayed by about a quarter, that's not necessarily a bad thing. Research shows that applying a lag to institutional holdings can generate positive alpha in some cases. That's all the more reason to crack open the moves being made with pro investors' $21 trillion under management.

We're still pretty early in 13F filing season. Think of the early results as a "sneak peek" at what institutional investors are doing more broadly with their money in the last quarter. Without further ado, here's a closer look at five stocks fund managers love right now.

Exxon Mobil

Image placeholder title

Up first on the pros' list of favorite stocks is energy giant Exxon Mobil (XOM) - Get Report . As energy prices have rebounded in 2016, Exxon has been one of the big beneficiaries, rallying 17% since the calendar flipped to January. And while the energy sector has been correcting in June, Exxon Mobil hasn't been so quick to reverse course -- this stock's momentum story still looks strong as we head into August.

Exxon Mobil is the biggest integrated energy company on the planet. Last year, the firm produced 2.1 million barrels of liquids and 11.1 billion cubic feet of natural gas per day. And it's able to keep up that pace in the long run. Exxon's proved reserves totaled 25.3 billion barrels of oil equivalent last year. Besides its huge production business, Exxon is also the world's largest refiner and a major chemical producer. Those operations further downstream have helped to reduce Exxon's commodity risk at the same time that peers have been breaking off their downstream operations.

Exxon's size comes with some major advantages in this environment -- and we saw that play out in 2015, as less massive E&P stocks got pummeled by the rout in commodity prices. Exxon's financial strength and staying power gives it the ability to weather slow periods for the energy sector, potentially taking advantage of acquisition opportunities in smaller distressed E&P stocks along the way.

Early filing funds added 4.37 million shares of Exxon to their portfolios in the most recent quarter, a $400 million buy operation at current price levels.

AT&T

Image placeholder title

AT&T (T) - Get Report  is another big-name stock that funds flocked to in the second quarter -- and another one that saw some outstanding performance in the first half of the calendar year. Year-to-date, AT&T is up more than 27% on a total returns basis, leaving the rest of the S&P 500 in its dust. Along the way, pro investors added approximately a million new shares of AT&T to their portfolios, making it another of the most-bought stocks among the first batch of filers for the second quarter.

AT&T proves that being No. 2 comes with some big benefits. The firm is the second-largest wireless carrier in the country, boasting more than 100 million customers. AT&T is also the local telephone company for customers in 21 states, providing the typical trio of voice, internet and TV services. And finally, the firm is one of the biggest satellite TV providers in the Americas, thanks to its acquisition of DirecTV, which added 20 million U.S. satellite subscribers as well as a footprint almost that big in Latin America.

The delay from the Fed in raising interest rates comes with some unintended upside consequences for dividend stocks like AT&T. As one of the highest-yielding stocks in the S&P 500, AT&T becomes relatively more attractive to income investors as long as rates remain low and income alternatives remain few and far between. Look for that environment to continue to fuel momentum in AT&T, given this stock's hefty 4.5% dividend yield.

Walmart Stores

Image placeholder title

Walmart Stores (WMT) - Get Report  started the year as one of the best-performing large-caps on the market -- and pro investors took note. At the same time, Walmart's momentum has persisted in 2016, with shares up more than 20% since the calendar flipped to January. That makes the buying 5.81 million shares early filing institutions picked up last quarter look pretty prescient. The question now is whether it still makes sense to buy the gigantic retailer.

Walmart is the largest retailer on the planet, with more than $485 billion in annual revenue. At a time when online sales are the growth space in retail, Walmart is the anti-Amazon.com -- the firm generated the vast majority of its sales in its network of 11,528 brick-and-mortar retail stores last year. What Walmart lacks in sex appeal and growth, it makes up for in profitability: the firm has raked in more than $14.4 billion in profits in the last 12 months.

Compared with its digital rivals, Walmart still looks relatively cheap, even despite the nonstop rally shares have enjoyed this year. The firm's ability to assert pricing pressure on suppliers should keep prices low and net margins positive in 2016. Ironically, Walmart was actually one of hedge funds' most-hated stocks back in February, but they've made an about-face as Walmart has consistently outperformed this year. It looks like hedge funds are finally back on the right side of the trend.

SPDR Gold Shares

Image placeholder title

Only one exchange traded fund made our list of hedge funds' favorite stocks this past quarter -- and it shouldn't be very surprising that it was the SPDR Gold Shares ETF (GLD) - Get Report . Gold prices have been on fire in 2016, and GLD has been a stellar performer, up more than 24% year-to-date. Like with income plays AT&T and Walmart, metals investors have the Fed to thank for that surge in demand for gold. Increased anxiety in the financial markets has been translating into a sustained rally in the price of everyone's favorite precious metal.

And funds are buying GLD in a big way. Early filings showed 3.9 million shares of GLD got added to pro portfolios during the most recent quarter -- that's a $491.4 million buying operation at current price levels. Even more significant, those same funds only held 4.9 million shares of GLD a quarter ago, which means that they increased their holdings in this big ETF by about 80%. That's a conviction bet if there ever was one.

GLD is a popular option for investors looking to get exposure to metals because this fund is designed to reflect the price action in gold bullion, something that most individual investors don't have easy, low-cost access to. The ETF is backed by physical gold, and the trust's expense ratio of 0.4% makes it one of the lowest-cost ways to get exposure to precious metals pricing. While gold prices have corrected a bit in July, this uptrend is still very much in effect in GLD right now, which means it's a solid option to follow the pros on this summer.

Digital Realty Trust

Image placeholder title

Last up on our list of funds' favorite stocks is Digital Realty Trust (DLR) - Get Report , a $15 billion real estate investment trust that owns technology-focused properties worldwide. No surprise, Digital Realty is another income play, which means that funds are largely buying stocks based on the macro story in 2016 -- specifically, the odds that we won't see another meaningful interest rate hike any time soon. The first round of 13F filers added 1.48 million shares of Digital Realty to their portfolios last quarter, hiking their exposure to this REIT by 15%.

Digital Realty Trust owns more than 150 datacenters, internet gateways, and manufacturing facilities, comprising more than 22.8 million square feet of leasable space. The datacenter niche gives Digital Realty a valuable corner of the real estate market, helping the firm profit as demand for data storage and server rack space continues to move up and to the right.

Like other commercial REITs, DLR enters into long-term triple-net leases with tenants, an arrangement that takes most of the risks off of DLR's balance sheet and puts the onus on tenants instead. Tenants pay for insurance, maintenance and property taxes, while paying Digital Realty predictable long-term lease fees. The result is a predictable 3.4% dividend yield at current price levels, a factor that's been key to this stock's 39% rally in 2016. Chances are good that there's more upside left in DLR during the second half of the year.

Disclosure: This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.