Mukesh Ambani, 63, is now the eighth richest person on the planet. (File)

Mukesh Ambani has had a rollercoaster 2020, cutting a string of deals for his digital business, undergoing wild swings in his wealth and having his brother’s finances laid bare for the world to see.

Now he can add another chapter — eclipsing the fortune of Warren Buffett.

The chairman of Reliance Industries Ltd is now worth $68.3 billion, surpassing Warren Buffett’s $67.9 billion as of Thursday, according to the Bloomberg Billionaires Index.

Shares of Mr Ambani’s Indian conglomerate have more than doubled since a low in March as its digital unit got more than $15 billion in investments from companies including Facebook Inc and Silver Lake. This week BP Plc paid $1 billion for a stake in Reliance’s fuel-retail business.

While Mr Ambani’s wealth has jumped — he became the only Asian tycoon in the exclusive club of the world’s top 10 richest people last month — Mr Buffett’s fortune dropped this week after he gave away $2.9 billion to charity.

The 89-year-old, known as the Oracle of Omaha, has slipped down the rankings after donating more than $37 billion of Berkshire Hathaway Inc stock since 2006. Berkshire Hathaway’s stock performance has also underwhelmed recently.

Mr Ambani, 63, is now the eighth richest person on the planet, and Mr Buffett is ninth, according to the index, which started in 2012.

Thanks to Mr Ambani’s deals, India has emerged as a hot-spot for M&A this year, accounting for more than 12% of those announced in Asia Pacific — the highest ratio since at least 1998.