Marc Andreessen quoted Warren Buffett this week. The legendary venture capitalist blasted the investor's bitcoin views in 2014.

• Marc Andreessen's best piece of investing advice is to "put all your eggs in one basket."
• The venture capitalist attributed the quote to Warren Buffett despite their bitcoin clash in 2014.
• Buffett doesn't see Berkshire Hathaway as a single basket, given its varied businesses.

Marc Andreessen revealed in a recent Bloomberg interview that his favorite piece of investing advice is: "Put all of your eggs in one basket and watch that basket closely." The legendary venture capitalist attributed that quote to Warren Buffett (it appears to date back to Andrew Carnegie in 1885), which is striking as Andreessen has blasted the Berkshire Hathaway CEO in the past, and Buffett doesn't exactly follow that mantra.

Buffett warned investors to avoid bitcoin in 2014, labeling it a "mirage" and describing the idea that it's inherently valuable as "just a joke." He compared the cryptocurrency to a check or money order, dismissing it as just another method of transmitting money.

Andreessen, the cofounder of Andreessen Horowitz, shrugged off Buffett's bitcoin critique as ignorant at a CoinSummit event that year. "The historical track record of old white men who don't understand technology crapping on new technology is at 100%," he said, according to his interviewer.

The venture capitalist elaborated on Twitter shortly afterward. He described Buffett as a "personal hero" of his and a "world-class expert in many areas," CNBC reported, but he didn't value the Berkshire chief's uninformed opinion of bitcoin.

"I know nothing about railroads," he added, likely referring to Berkshire's ownership of the BNSF Railway. "Correspondingly have no view."

Andreessen and Buffett both make concentrated wagers on businesses they like, whether it's a high-flying technology company like Facebook or Airbnb in the VC's case, or the likes of Geico and Bank of America for Buffett.

Although Buffett keeps more than 99% of his fortune in Berkshire stock, and 5 stocks make up 75% of his portfolio's value, he rejected the idea that he bets the farm on a single company during Berkshire's shareholder meeting in 2005.

"When we own Berkshire, we don't think of all our eggs being in one basket, because we have a lot of good businesses," Buffett said, underscoring the fact that Berkshire has scores of subsidiaries including See's Candies and PacifiCorp.

Still, Buffett would undoubtedly agree with Andreessen's recent recommendation of a S&P 500 index fund over something "fancy." Buffett has encouraged the vast majority of people to invest in tracker funds for years, and instructed that 90% of his estate be invested in a S&P 500 index fund for his wife upon his death.