Billionaire investor Warren Buffett said Monday he's not buying Apple shares, but would if they continued to lose ground.

"If it were cheaper, we'd be buying it. We aren't buying it here," Buffett said in an interview with CNBC "Squawk Box" co-host Becky Quick. "I don't see myself selling – the lower it goes, the better. I like it, obviously."

Buffett has made Apple a keystone of his expansive holdings and highlighted his own use of the company's products. He said at his annual shareholders' meeting in Omaha last May that "we would love to see Apple go down in price," so he could buy more at a bargain.

In Monday's interview, Buffett reiterated that while the latest SEC filings showed that Berkshire Hathaway had slightly trimmed its Apple stake in the fourth quarter, it was one of the conglomerate's money managers — Ted Weschler or Todd Combs — who decided to sell some Apple to make a new investment. Weschler and Combs have a capped amount of money to invest.

Apple last year became the first publicly traded U.S. company in modern history to reach $1 trillion in market value, but it's now worth $832 billion. Berkshire Hathaway is the second-largest holder of Apple shares with a stake worth about $43 billion, according to FactSet.

Despite Wall Street's concerns surrounding the iPhone maker's device sales, Buffett has often explained that his love for Apple stems less from short-term financial performance and more from the power of its brand and ecosystem. Buffett views Apple more as a compelling consumer stock than a tech stock thanks to its popularity among its many users.

"I do not focus on the sales in the next quarter or the next year," he said in August. "I focus on the ... hundreds, hundreds, hundreds millions of people who practically live their lives by it [iPhone]." He also called the iPhone "enormously underpriced" at that time, saying that it's worth far more than the $1,000 Apple charges.

Apple stock is down about 20 percent over the past six months, with much of that decline following the company's decision to no longer break out individual sales numbers for the iPhone, iPad and Mac, a statistic analysts and investors for years used as a proxy for Apple's financial health.

Investors were also spooked after the company lowered its first-quarter guidance last month. Apple lowered revenue guidance to $84 billion, down from the $89 billion to $93 billion it had previously projected. The company lowered its gross margin to about 38 percent from a range of 38 percent to 38.5 percent.

Buffett also discussed Berkshire's $112 billion cash pile and how he plans to use it. He also detailed his outlook on the U.S. economy, his views of the early 2020 presidential campaign field and his investment in Kraft Heinz.