Billionaire investor Warren Buffett may not be one of your Facebook friends, but you can still know what stocks he's buying. Big time investors like Buffett submit a 13F report to the Securities and Exchange Commission every quarter highlighting what stocks they're buying and selling. Last quarter, Warren Buffett boosted his exposure to Wells Fargo (WFC -0.91%), Deere & Co. (DE -0.87%), and Liberty Global plc (LBTYA -0.88%). Let's take a closer look at why the Oracle of Omaha wants to own more of these companies and if they might be worth owning in your portfolio too.

Bigger spreads, bigger profit
Wells Fargo has been a big holding for Warren Buffett's Berkshire Hathaway (BRK.B -0.56%) (BRK.A -0.39%) for years and last quarter, Buffett increased his stake in the nation's biggest mortgage lender by 9.4 million shares.

Buffett now owns 479.7 million shares in Wells Fargo and since he's the bank's biggest shareholder it's pretty clear that he thinks that the bank's got plenty of opportunity ahead of it. The economy continues to grow, albeit tepidly, and with the Federal Reserve shifting to rising interest rates, spreads between borrowing and lending rates should widen, providing profit tailwinds.

Last quarter, total average loans grew 7% to $912.3 billion, and net income totaled $5.7 billion. Net income for the full year was $23 billion, in line with 2014, and rising short term rates could help lift results in 2016. The bank cited higher short term rates as one reason why its net interest income jumped $131 million year-over-year in Q4.

Given the bank enjoys solid loan demand, boasts arguably best-in-show financials, and its shares yield about 3%, investors might want to join Warren Buffett by making Wells Fargo a core holding in their portfolios too.

SOURCE: DEERE & CO

Planting seeds for growth
Warren Buffett also bought more shares in agricultural equipment maker Deere & Company.

Berkshire Hathaway added 5.8 million shares of Deere & Co and it now owns 22.9 million shares in the company overall.

The 34% increase in Buffett's stake suggests confidence that worry over global economic growth in Asia and Europe will ease and that rebounding crude oil prices will correlate to a bounce back in grain prices that could support equipment demand.

Last quarter, Deere & Co's management reported fiscal first-quarter sales fell 13% year over year, and it forecast an additional 10% drop in 2016.

That's not very bullish, but it appears that Warren Buffett is willing to play the long-game and assume that this is about the worst it will get for Deere & Co. If so, it might not be a bad bet. Even with all the headwinds, Deere & Co's c-suite still thinks it will deliver earnings of $1.3 billion this year.

Global quad play
Following the purchase of 587,011 shares last quarter, Berkshire Hathaway's 12.5-million-share position makes it Liberty Global's third biggest shareholder.

Warren Buffett has always been a fan of great management teams and arguably there's no better media CEO than Liberty Global's John Malone. Malone has been busy transforming Liberty Global into European leader in media services and recent deals that expand it into mobile position it nicely to pitch quad-play (television, telephone, internet, and mobile) services to subscribers.

Earlier this month, Liberty Global reported its partnering with Vodafone to create a joint-venture in the Netherlands to offer quad-play services and last year, Malone spent $1.3 billion acquiring Belgian mobile operator Base.

Because Liberty Global's subscribers provide it with mountainous free cash flow that's growing thanks to new services, Warren Buffett may keep this position for the long haul and if so, then Liberty Global shares may be worth owning.