LONDON (BLOOMBERG) - The leveraging of a giant social media presence, a catchy tune about a family of sharks and a burgeoning collection of junkyards are just a few of the curious ways that helped make 2019 a fertile year for fortunes to blossom around the world.

Kylie Jenner became the youngest self-made billionaire this year after her company, Kylie Cosmetics, signed an exclusive partnership with Ulta Beauty Inc. She then sold a 51 per cent stake for US$600 million (S$811.50 million).

It has been almost two months since the Washington Nationals captured their first World Series championship, but people around the world are still singing along to the baseball team's adopted rallying cry: "Baby Shark, doo-doo doo-doo doo-doo."

The Korean family that helped popularise the viral earworm are now worth about US$125 million.

Even car wrecks proved to be a treasure trove. Mr Willis Johnson, the gold-chain-wearing Oklahoma native who founded Copart Inc, has amassed a US$1.9 billion fortune by building a network of junkyards to sell damaged autos.

The emergence of atypical fortunes underscores just how much money the uber-rich accumulated in 2019.

And the richer they were at the start of the year, the richer they got. The world's 500 wealthiest people tracked by the Bloomberg Billionaires Index added US$1.2 trillion, boosting their collective net worth 25 per cent to US$5.9 trillion.

Such gains are sure to add fuel to the already heated debate about widening wealth and income inequality.

In the US, the richest 0.1 per cent control a bigger share of the pie than at any time since 1929, prompting some politicians to call for a radical restructuring of the economy.

"The hoarding of wealth by the few is coming at the cost of peoples' lives," Representative Alexandria Ocasio-Cortez, a self-described democratic socialist, said in a Dec 12 tweet as the UK began to vote.

Still, the defeat of Britain's socialist opposition leader Jeremy Corbyn, whose campaign included attacks on billionaires and calls to "rewrite the rules of our economy", gave an added boost to mega-fortunes.

Leading the 2019 gains was France's Bernard Arnault, who added US$36.5 billion as he rose on the Bloomberg index to become the world's third-richest person and one of three centibillionaires - those with a net worth of at least US$100 billion.

In all, just 52 people on the ranking saw their fortunes decline on the year.

Amazon.com Inc's Jeff Bezos was down almost US$9 billion, but that drop is because of his divorce settlement with Ms MacKenzie Bezos. The e-commerce titan is still ending the year as the world's richest person.

Here's what the year looked like for the 0.001 per cent:

2019 WINNERS

- The 172 American billionaires on the Bloomberg ranking added US$500 billion, with Facebook Inc's Mark Zuckerberg up US$27.3 billion, while Microsoft Corp co-founder Bill Gates rose US$22.7 billion.

- Representation from China continued to grow, with the nation's contingent rising to 54, second only to the US. Mr He Xiangjian, the founder of China's biggest air-conditioner exporter, was the standout performer as his wealth surged 79 per cent to US$23.3 billion.

- Russia's richest added US$51 billion, a collective increase of 21 per cent, as emerging market assets from currencies to stocks and bonds rebounded in 2019 after posting big losses a year earlier.

2019 DECLINES

- Rupert Murdoch's personal fortune dropped by about US$10 billion after proceeds from Walt Disney Co's purchase of Fox assets were distributed to his six children, making them billionaires in their own right.

- Interactive Brokers Group Inc's Thomas Peterffy saw his wealth slump by US$2.1 billion as investors weighed a reshaped competitive landscape for brokerage businesses after rival Charles Schwab Corp eliminated commissions and agreed to buy TD Ameritrade Holding Corp.

- WeWork's Adam Neumann saw his fortune implode - at least on paper - as the struggling office-sharing company's valuation dropped to US$8 billion in October from an estimated US$47 billion at the start of the year. Still, SoftBank Group Corp's rescue package left Mr Neumann's status as a billionaire intact.

NEW BILLIONAIRES

- White Claw, the "hard seltzer" that was the hit of the summer among millennials, helped boost Mr Anthony von Mandl's net worth to US$3.6 billion.

- Mastering the art of fast-food deliveries proved rewarding for Mr Jitse Groen, whose soaring Takeaway.com NV lifted his wealth to US$1.5 billion.

- The popularity of soy milk gave eight members of Hong Kong's Lo family a combined US$1.5 billion.

Despite the widespread gains, plenty of the world's richest people may be happy to wave farewell to 2019.

The year included messy details of the Bezos divorce and the Jeffrey Epstein saga, which enveloped a who's who of financiers and entrepreneurs, after the convicted paedophile was arrested in July by federal agents after stepping off his private jet at Teterboro Airport in New Jersey.

Through it all, their bank balances remained robust, as a record bull market got a December kick with an easing of trade tensions between the US and China, a resolution to Britain's political stalemate and a blowout US jobs report.