In 2017, he said he wouldn’t have become president without it.

“Twitter is a wonderful thing for me, because I get the word out… I might not be here talking to you right now as president if I didn’t have an honest way of getting the word out,” he said.

After Twitter’s new owner Elon Musk reversed Mr Trump’s permanent suspension, you might have thought the former president would jump at the chance to come back. But so far, he hasn’t taken up that offer.

Why?

Well, only Donald Trump knows the answer to that question for sure.

But what we do know is he has a lot of money to lose from tweeting.

“The simplest explanation is the most likely – it’s about money,” says Josh Tucker, professor of politics at New York University (NYU).

After Donald Trump was kicked off Twitter, he created his own social media platform called Truth Social – that looks an awful lot like Twitter.

To understand the financial bind Donald Trump is in, you have to understand the complex nature of Truth Social’s business set up.

Last year, the private company that owns Truth Social, Trump Media & Technology Group (TMTG), announced its intention to merge with a shell company trading on the stock exchange called Digital World Acquisition Corp (DWAC).

DWAC is what’s known as a Special Purpose Acquisition Company (Spac). Spacs are hyped as a way to speed up the often slow process of taking a private company public. In simple terms, it means merging a company that isn’t on a stock exchange with one that is.

Both TMTG and DWAC have agreed to merge, though the deal has not yet been completed. But that hasn’t stopped investors piling money into DWAC – all of them speculating that the deal will go through. The shell company is currently valued at more than $800m (£665m).