But now there's one more to add to a list: Their response to climate change. And more specifically, the role billionaires can have in countering its effects.
In a recent blog post, the Virgin Group founder said he and Gates met last week and discussed their shared view on investing in "long-shot" ideas that aim to combat the problem.
"Not all ideas will work but if we back enough of them, then the more likely it is that there will be a handful that can have a huge impact," Branson wrote.
The pair were in Paris for the One Planet Summit – a meeting designed to address the challenges of climate change – during which Gates announced the expansion of his Breakthrough Energy Coalition (BEC).
The BEC is a group of high net worth investors who have made commitments to funding $1 billion worth of "next-generation" energy technologies globally. The coalition, spearheaded by Gates, features high profile business figures including Jeff Bezos, Marc Benioff, Jack Ma, Mark Zuckerberg and Branson himself.
So far, the project has invested in a variety of ambitious energy solutions, including businesses developing solar energy grids and electric vehicle batteries, as well as a biotech company developing new ways to grow sustainable, edible protein.
"As a partner in the project, I agree with Bill that it has never been more pressing to find clean energy innovations that can change the world," Branson wrote.
The initiative is close to Branson's heart, not least because of the links climate change is said to have had to the 2017 hurricanes that wreaked havoc on the British Virgin Islands, including Branson's own Necker Island.
"It's so important that we keep working to find ways to innovate and scale up clean energy solutions," Branson's post read.
The airline owner has previously weighed in on the climate change debate, earlier this year touting his idea for a "clean energy dividend" – an iteration of carbon taxes — which would charge companies for the fossil fuels they use and carbon emissions they cause.
"Unlike a carbon tax, that money wouldn't disappear into government coffers, but would be used specifically to be invested in generating clean energy through wind farms and solar panels, as well as the development of more low carbon fuels and other breakthrough technologies," Branson wrote in a March post.
"This is a win-win all-round," he added.
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