Nick Clegg made almost $19m from the sale of shares in Meta during his six-year term at the owner of Facebook, Instagram and WhatsApp, filings show.

The former British deputy prime minister had sold $18.4m (£14.8m) worth of shares in the group before announcing on Thursday that he was leaving his role as its president of global affairs and communications.

His total pay at Meta has not been disclosed but he still holds almost 39,000 of the company’s shares, worth about $21m at their current price.

He will be replaced by his deputy, Joel Kaplan, who as a former deputy chief of staff for policy under the former president George W Bush is known to be the most prominent conservative voice at the company.

People close to Clegg said the decision to leave Meta was his own, though Kaplan had been long talked about as a possible successor should the Republicans win the White House.

Speculation is rife about what the 57-year-old may do next, and whether he may countenance a return to politics. The Liberal Democrats won a record number of seats for the party at the general election last year.

The former party leader has not decided where he will work next, though allies say he is looking to take on a job in the field of artificial intelligence. Clegg has argued against the regulation of AI, criticising the former prime minister Rishi Sunak last year for focusing on the dangers rather than the opportunities of the technology.

Clegg is understood to agree more with Tony Blair, another former prime minister, who has become one of the most prominent evangelists for the potential of AI to improve public services. In September, Clegg said: “I think we wasted a huge amount of time going down blind alleys, assuming that this technology was going to eliminate humanity and we’re all going to be zapped by a robot with glowing red eyes.”

Friends say Clegg is open to job opportunities in the public or private sector and wants to remain in Europe, having moved back to London in 2022. His wife, Miriam, is known to have political ambitions of her own and recently set up a thinktank in her home country of Spain.

Clegg, who was knighted in 2018 for political and public service, was heavily criticised when he took up the role later that year as Facebook’s vice‑president for global affairs and communications.

At the time he was a leading supporter of the People’s Vote campaign and part of a high-powered pro-remain group of former politicians lobbying to stop Brexit.

Explaining the reason for his abrupt exit from the fight, Clegg wrote in the Guardian that, once he had signed up to join the Silicon Valley company and decided to relocate to the US, he might as well leave as soon as possible.

Nonetheless, his decision to accept the high-profile role, at a time when Meta was struggling to cope with mounting political pressure over issues including fake news, data protection and government regulation, has proved to be hugely lucrative.

Filings at the US Securities and Exchange Commission (SEC) show that Clegg’s most recent sale of shares was in November at a market value of just over $4m, although the exact gross proceeds of the latest transaction have yet to be made public.

He was promoted to president of global affairs at Meta in 2022 – reporting directly to the founder and chief executive, Mark Zuckerberg. Clegg partly relocated to London that year, splitting time between the UK and California.

Clegg wrote in a post on Facebook on Thursday: “It truly has been an adventure of a lifetime! I am proud of the work I have been able to do leading and supporting teams across the company to ensure innovation can go hand in hand with increased transparency and accountability, and with new forms of governance.”

As Lib Dem leader he managed to get his party into power through a coalition with David Cameron’s Conservatives in 2010 but resigned as leader five years later after taking the blame for his party’s 2015 election defeat, which he described as “immeasurably more crushing and unkind” than he had feared.

He lost his seat in the 2017 general election and subsequently said that he “never had any desire to sit in an unreformed House of Lords”.

Meta was approached for comment.