SEOUL — Go to a store, hop in a taxi or even stop by a street peddler's cart in China, and you will see QR codes strung up on colorful laminated squares. These mobile payment codes are the default way money changes hands in China these days, and the reason Ant Group's initial public offering is set to be the world's largest.

China’s Ant Group — the Alibaba spinoff behind the ubiquitous blue QR payment codes across the world’s second-largest economy — announced plans on Monday to raise more than $34 billion in a joint listing across Shanghai and Hong Kong. This would trounce last year’s listing of oil titan Saudi Aramco, the reigning IPO champion.

Mobile payments have replaced cash and credit cards in China as the preferred payment method, thanks to easy-to-use apps made by Ant Group and its closest rival, Tencent. Ant Group’s Alipay and Tencent’s WeChat Pay are similar in spirit to wildly popular U.S. stock trading app Robinhood, in that they are user-friendly enough that anyone with a smartphone and bank account can make complicated financial transactions with a click or swipe.

It’s the second time that Alibaba’s founder, Jack Ma, is seeing one of his companies attain the status of biggest IPO in history. Alibaba, the Chinese e-commerce giant, captured the title when it was listed on the New York Stock Exchange in 2014.

Duncan Clark, chairman of consulting firm BDA China and author of “Alibaba: The House that Jack Ma Built,” said the repeat success is a testament to Ma’s ability to tap into China’s vast population of small merchants, being a former one himself. In Ma’s early entrepreneurial days, he made ends meet selling carpets on the street.

“It reflects his understanding of the mind-set of the merchants and consumers, and his demonstrated ability to put in qualified management teams without hovering over them,” Clark said.

Ma officially retired from Alibaba last year, and Ant Group was spun off from Alibaba in 2014, after a decade as Alibaba’s in-house payment processing arm.

In an open letter to investors last week, Ant Group Executive Chairman Eric Jing reaffirmed the company’s longtime strategy of providing financial services to small businesses.

“As long as we can let each mom-and-pop store and street stand acquire loans as easily as large companies, to have the same development opportunities . . . then Ant Group will certainly be one of the future’s companies,” he wrote.

Alipay and WeChat Pay have expanded from mobile payments to loans, investment funds, insurance and other financial products, all available with a click in their apps. This growing array of services has bolstered Ant Group to an expected $310 billion valuation for its IPO. It has more than 700 million monthly users.

Ant Group began as the escrow service for Alibaba, an intermediary that shuttled funds from online shoppers to product vendors. As a pioneer in Internet finance, it clashed for years with China’s financial regulators and has at times been slapped with fines.

Ant Group has ultimately been accepted by Beijing regulators, after some compromises, as it’s the type of innovative tech company China is trying to promote. Along with Huawei and Tencent, it is one of the Chinese companies that has managed to speed ahead of Western counterparts in its sector.

Unlike Alibaba’s IPO in 2014, Ant Group is passing over Western stock markets at a time of U.S.-China conflict. It is aiming to raise more than $17 billion each in Hong Kong and Shanghai, with individual shares priced at roughly $10.30.

Liu Yang in Beijing contributed to this article.