Elon Musk renewed his feud with Bill Gates in a series of tweets in which he slammed his fellow tech billionaire for holding a short position on Tesla shares worth as much as $2 billion.

Musk revisited the issue shortly after he shared a poll asking his Twitter followers whether they found politicians or billionaires to be less trustworthy. More than 75% of the respondents said they trusted politicians less.

One follower quipped that they trusted Musk but not Gates, prompting the Tesla CEO to call out Gates’ bet against his electric vehicle firm.

“Since Gates still has a multi-billion dollar short position against Tesla while claiming to help with global warming, I guess I have some trust issues with him too,” Musk tweeted in response.

Musk’s disagreement with Gates drew public scrutiny beginning in April. A text message exchange between the two tech titans revealed that Musk had confronted Gates regarding his $500 million short position on Tesla shares.

In another tweet last week, Musk claimed that the $500 million stake was now worth far more money because Tesla shares had risen in value since Gates made the move.

“It was $500M, but then Tesla went up a lot, so now it’s $1.5B to $2B to close it out,” Musk said.

Since it’s unclear when Gates took his short position in Tesla, Musk’s math couldn’t be confirmed. The company’s stock is up 23% over the last 12 months, but it’s also down more than 35% from its level on Jan. 1 as Tesla and other large-cap tech stocks contend with difficult market conditions and Musk pursues an acquisition of Twitter.

Gates has yet to publicly respond to Musk’s tweets.

The original text message spat between Musk and Gates surfaced on a pro-Musk Twitter account, @wholemarsblog, which is run by Omar Qazi. Musk later confirmed they were authentic. Gates had texted Musk to “discuss philanthropy possibilities.”

“Sorry, but I cannot take your philanthropy on climate change seriously when you have a massive short position against Tesla, the company doing the most to solve climate change,” Musk texted Gates at the time.

Musk escalated the feud after the texts surfaced, sharing a tweet comparing a photo of Gates to an emoji depicting a pregnant man.

Gates downplayed the viral exchange during an appearance at the The Wall Street Journal’s CEO Council Summit earlier this month, telling an audience that Musk’s mockery didn’t bother him.

“I don’t think whether one is short or long on Tesla is a statement about your seriousness about climate change. I’m putting billions of dollars into climate change innovation. I applaud Tesla’s role in helping with climate change,” Gates said.

At the same event, Gates raised questions about Musk’s bid to buy Twitter – arguing his policy ideas could make the platform “worse.”

“He actually could make it worse,” Gates said at the event. “That’s not his track record – his track record with Tesla and SpaceX is pretty mind-blowing with putting together a great team of engineers and taking the people who worked in those fields in a less bold way and really showing them up.”

“I kind of doubt that will happen this time, but we should have an open mind and never underestimate Elon,” Gates added. “What’s his goal? Where he talks about the openness, how does he feel about something that says ‘vaccines kill people’ or ‘Bill Gates is tracking people’ – is that one of the things he thinks should be spread?”