Elon Musk rejects the 'investor' label, saying he isn't Warren Buffett. He's drawn that line before.

• Elon Musk rejects the label of 'investor' and says he's not Warren Buffett in a new tweet.
• The Tesla chief sees himself as an engineer and innovator, not a capital allocator like Buffett.

Elon Musk has drawn a line between himself and Warren Buffett once again, underscoring that he sees himself as a builder of businesses and products, not an investor.

"You have the 'invests in Tesla' part wrong," he replied on Sunday to a tweet summarizing his career path. "Do I look like Warren f* Buffett to you?"

Buffett specializes in identifying undervalued companies with high-quality management, then uses Berkshire Hathaway's money to buy a stake in them or acquire them outright. He's structured his conglomerate as a web of autonomous, decentralized businesses run by people he trusts, which frees him to focus on sniffing out bargains and shrewdly allocating capital.

In contrast, Musk is famously hands-on with his businesses. By all accounts, he's deeply involved in solving the technical challenges of bringing self-driving cars and multiplanetary spaceships into reality. While he didn't found Tesla, few would deny that he's shaped the company and spearheaded its success for close to two decades now.

The Twitter owner and CEO of Tesla and SpaceX has previously underlined the differences between the Berkshire CEO and himself.

"I'm not Warren Buffett," Musk told Tesla analysts in October. "I'm not an investor. I am an engineer and manufacturing person and a technologist."

"I actually work and design and develop products," he continued. "We're not going have a portfolio of investments or whatever."

Musk has gone as far as panning Buffett's job — studying companies and deciding which ones deserve his capital — as "super boring." He's also cast doubt on the investor's public image as a "kindly grandfather" and said he's not the stockpicker's "biggest fan."

Yet the tech billionaire has praised Buffett's exceptional ability and the economic value of his work, and hinted he would welcome him as a Tesla shareholder. Musk has also quoted Buffett several times over the years — including on Tesla's earnings call last week — and expressed a desire to meet him back in 2008.

As for Buffett, he's previously questioned why Musk tweets himself into trouble, and once challenged him to disrupt Berkshire-owned See's Candies — which Musk briefly tried to do before giving up.

More recently, Buffett has hailed Musk's unlikely success with Tesla, and saluted the serial entrepreneur's dedication to tackling incredibly tough problems.

"It's a dedication to solving the impossible, and every now and then he'll do it," Buffett said during Berkshire's annual shareholder meeting this year.

The investor added that Musk's all-consuming approach to his work doesn't appeal to him, but the Tesla boss "wouldn't enjoy being in my shoes either."