Warren Buffett is well known for his stock-picking acumen. As I wrote in a recent article, some of Buffett's stock investments have increased more than tenfold since he bought them for Berkshire Hathaway's (NYSE:BRK-A) (NYSE:BRK-B) portfolio.

So it may surprise you to learn that it's not only Buffett calling the shots in Berkshire's stock portfolio anymore. Within the past several years, Buffett has added two stock-pickers to the mix, and they've been responsible for some of Berkshire's most notable recent stock investments. Here's a quick background on Ted Weschler and Todd Combs, and what the pair's role could evolve into, especially when Buffett is no longer running Berkshire.

Meet Ted and Todd

For much of the time Buffett has been at the helm of Berkshire Hathaway, he has managed the company's stock portfolio all by himself. However, that has changed in recent years with the hiring of two investment managers, Todd Combs and Ted Weschler, who were hired in 2010 and 2011, respectively.

Both men are hedge fund veterans with impressive track records. For example, Weschler's fund delivered 1,236% in gains in just 11 years before he closed it -- roughly 9 times the gain of Buffett's stock portfolio during the same time frame.

Combs ran a hedge fund from 2005 to 2010, and his returns over that period were 34%. That may not sound too impressive, but recall that this time period contained the Great Recession, and the S&P 500's total return was just 2.9% for those years, so it's fair to say that Combs' fund beat the market by a considerable margin. A significant component of Buffett's investment strategy is to consistently beat the market in bad years, so this may be one factor that made Combs attractive for the position.

Weschler initially met Buffett as the winner of two charity auctions, in 2010 and 2011, where the prize was a lunch with Buffett himself. Weschler's winning bids: $2,626,311 and $2,626,411 -- a total of more than $5.2 million. Reportedly, Weschler's investment success -- and, more importantly, how he achieved it -- impressed Buffett at the lunches.

The results have been strong so far

Buffett told CNBC in an interview that hiring the pair is "one of the best decisions that Charlie [Munger] and I have ever made." He's even gone so far as to say that "they've made more money than I would have" with the capital they've been entrusted with.

Weschler has reportedly opened Buffett's eyes to sectors he had previously avoided, specifically technology. For example, Buffett's Apple (NASDAQ: AAPL) investment started as a roughly $1 billion stake in early 2016 and was reportedly initiated by Weschler. Buffett himself has increased the position many times over since then.

Combs has also changed Buffett's thinking in a few instances. It was Combs who reportedly convinced Buffett to acquire the Duracell battery brand and get rid of Berkshire's position in Procter & Gamble (NYSE: PG) stock.

And the pair have made some pretty successful investments for Berkshire themselves in their relatively short tenure. For example, their first notable win was DIRECTV, of which about 36.5 million shares were acquired in the ball park of $42 to $47 per share. The bulk of it was converted into AT&T stock and cash when the telecom giant acquired the company in 2015, at a valuation of more than $93 per share.

Increasing responsibilities

Since Weschler and Combs started at Berkshire, they have been given an increasing amount of Berkshire's money to invest. As of Buffett's 2016 letter to shareholders, each man manages over $10 billion -- about $21 billion altogether, which includes $7.6 billion of the pension trust assets of Berkshire subsidiaries. This is still a small fraction of Berkshire's roughly $150 billion stock portfolio, but it's far more than the $2 billion Buffett says they started with.

And Buffett stresses that each manages this money independently. In fact, Buffett says he usually doesn't learn about investment decisions they've made until he looks at Berkshire's monthly trade sheets.

In addition to their stock-picking responsibilities, both men have some of Berkshire's operating subsidiaries reporting directly to them, Combs confirmed in a recent interview.

Their future role at Berkshire

After Buffett picked Berkshire's stock investments himself for years, it may seem strange that he would reduce his role. However, it's important to point out that the reason Weschler (who is 56) and Combs (46) have been brought on, and given an increasingly large sum of money to invest, is that Buffett wants to make sure Berkshire's investment methods live on long after he's no longer at the helm.

In his 2014 shareholder letter, which marked 50 years of the Buffettera at Berkshire, Buffett laid out his vision for the next 50 years of Berkshire.

In the discussion, Buffett said that in the area of investments, "We are in fine shape for decades to come," referring to Weschler and Combs as "first-rate in all respects." He also said that they would continue to handle Berkshire's investment decisions and will be of particular help to the next CEO in evaluating acquisitions.

To sum it up, if you were wondering what Buffett's plans are for the future of Berkshire's closely watched stock portfolio once he's no longer at the helm, these two investment managers are it. And if their early performance is any indicator, it looks as if Berkshire investors will have their money in good hands.