Chinese e-commerce mogul Jack Ma's reported interest in buying Hong Kong's South China Morning Post (SCMP) has captured global attention, but his Alibaba Group's 20-plus investments in mainland China's media sector since 2013 have also caused quite a stir.

His buying spree, which has sparked comparison between him and Australia-born media mogul Rupert Murdoch, began with an 18 per cent stake Alibaba took in the Sina Weibo microblog in 2013.

Other headline-grabbing moves include the takeover of video streaming giant Youku Tudou this month, in a deal believed to be worth a total of US$4.8 billion (S$6.8 billion), and a US$240 million stake in Huayi Brothers film studio late last year.

Alibaba, which now has a 32 per cent stake in Weibo, is also reportedly seeking to buy out online media firm Sina Corp, the parent of Weibo.

Most of the 24 investments, based on media reports, are in social media tools, video-streaming sites, online news portals and film. Only four are in traditional media firms like newspapers and magazines, and none appears to come close to the 112-year-old SCMP in stature.

Still, it is a remarkable about-turn for Mr Ma, who told a reporter four years ago that he was not keen on media ownership as it is linked to politics, said the Wall Street Journal.

Analysts believe that commercial considerations are the key reasons for Alibaba's investments, especially those in social and online media firms.

Mr Ma, who stepped down as chief executive officer in 2013 and is now Alibaba chairman focusing on strategy, said he believes there could be better synergy between media outlets and businesses that work with Alibaba, such as retailers on its e-commerce portals.

Speaking to Bloomberg TV earlier this month about his investments, he said the media can help small and medium-sized companies in promoting their products, while the "huge" advertising dollar gathered from the businesses can in turn help the media.

"And the media can definitely, using our data, tell the economy in an accurate way," he added.

Other commercial considerations cited include securing its own media platforms to shape public opinion or the image of Alibaba, cutting advertising costs and boosting revenue through increased interaction with readers and viewers.

Analyst Cai Ling of the CIConsulting industry research firm said Alibaba is playing catch-up with the other two Chinese Internet giants - Baidu search engine and Tencent media group - in the media sector.

Baidu, Alibaba and Tencent are referred to as BAT in China.

"Alibaba's strategy is to rapidly buy up media outlets to make up for its weakness," she told The Sunday Times. She said Alibaba, which has cornered some 80 per cent of China's e-commerce market, is also sitting on a valuable repository of big data material that it believes could be better used through its media platforms.

Analysts say investing in Sina Weibo reflects Alibaba's aim of boosting its social media presence against that of its competitors. Tencent's Wechat instant-messaging tool and its electronic wallet function are also seen as a rival to Alibaba's Alipay online-payment tool.

But some analysts say there is no discernible pattern nor method to Alibaba's expansion into the media and related sectors, judging by the diverse nature and scale of its investments.

A clue could come from Mr Ma's reply during an interview in July on why he has entered the film industry. "Whichever sector Alibaba enters, it is because it is something China needs 10 years later. If something is already hot now, our principle is not to invest in it," he said.

The buying of traditional media proves to be a more intriguing move by Mr Ma, whose wealth stands at around US$22.5 billion. His interest in SCMP has been likened to Amazon founder Jeff Bezos' purchase of the Washington Post in 2013.

Bloomberg technology reporter Brad Stone said in an interview that it smacks of "arrogance" on Alibaba's part that it believes it could revive the newspaper sector that has seen declining profitability due to challenges from online and social media.

Others believe politics is another factor, particularly returning the favour to the government for its policy support in Alibaba's early years that has allowed it to become a world leader in e-commerce.

Mr Cai Wei, president of SAIC Capital Internet consultancy and a former journalist, said Mr Ma may be responding to Chinese President Xi Jinping's calls last year for the establishment of new media firms "that have strength, communication capacity, credibility and are influential".

Speaking to officials at a closed- door retreat, Mr Xi reportedly said the new groups should be "diversified, advanced and competitive" and the relevant state authorities should properly integrate and manage traditional and new media.

"Jack Ma's investments into media groups could be seen as fulfilling that responsibility, and we could see more of such investments," Mr Cai told The Sunday Times. "In a way, BAT's development today has had to do with the government's policy support. They have an obligation to respond when the government calls."