When Marriott International swooped in last November to trump a smaller rival’s offer for Starwood Hotels and Resorts, the last-minute upset was set to create the world’s largest hotel company by rooms.

But if a group led by Chinese insurer Anbang has its way, those plans will not only unravel but also establish a new challenger in the global lodging industry with ambitions to grow rapidly through acquisitions.

On Monday, Starwood revealed it had begun talks with an unnamed group — later confirmed as a consortium led by Anbang — that has offered almost $13bn for the owner of the Sheraton, W Hotels and St Regis chains.

The all-cash bid from the Chinese group is worth $76 a share, Starwood said, adding that it remained committed to its already agreed deal with Marriott. However, the US company noted the value of Marriott’s cash-and-stock offer had fallen to $63.74, driven by a decline in that company’s stock price since November.

For Anbang, which started as a regional car insurance business in China 12 years ago, a Starwood takeover would be the climax of a rapid transformation into a diversified investment group. Over the past 18 months, Anbang has spent more than $23bn — without counting its offer for Starwood — to accumulate a sprawling list of global assets that span financial services, real estate and lodging.

Led by Wu Xiaohui, its politically connected chairman, Anbang has used the income from its growing insurance business to fund its overseas ambitions. The company had assets worth more than Rmb800bn ($123bn) as of February last year.

Mr Wu is married to the granddaughter of Deng Xiaoping, China’s former leader and the architect of the country’s transition out of a planned economy, and Anbang has an opaque ownership structure that includes associations with other prominent families. The company has also demonstrated what The Economist has called an “unusually good” ability to navigate China’s complex bureaucracy.

Analysts have questioned the company’s aggressive approach to M&A, saying Anbang risks undermining the profitability of its core business as it gambles on high-risk investments in other areas.

Growth expectations are being fuelled by China’s low rate of insurance penetration, giving providers room to catch up with western peers. Premiums were only 3 per cent of China’s gross domestic product in 2014, compared with 7 per cent in the US and 11 per cent in Japan, according to Swiss Re.

However, in China’s life insurance market, Anbang is dwarfed by listed rivals China Life and Ping An, with a market share of just 4 per cent.

To help manage its buying spree, the company has hired a handful of experienced investment bankers — following a pattern among Chinese companies with an appetite for overseas assets, including Alibaba and Fosun. By bringing talent in-house, several Chinese groups have been able to avoid using global investment banks for many of their deals.

As it has grown, the company’s connections have extended beyond its network in China. One of those has been with US alternative asset manager Blackstone, a relationship that has proved critical to Anbang’s expansion into lodging.

In late 2014, Blackstone sold New York’s landmark Waldorf Astoria hotel to Anbang for nearly $2bn and just this weekend agreed a $6.5bn sale of 16 prime US hotels to the Chinese group.

After the Waldorf deal, Mr Wu appeared at Harvard University to declare his “win-win” approach to business between the US and China. He also highlighted his budding friendship with Stephen Schwarzman, Blackstone’s chairman and chief executive, as well as Jonathan Gray, its head of real estate.

In that 2015 speech, Mr Wu said of Mr Gray: “Our relationship developed gradually from negotiation counterparties to close friends. I trust him deeply because he keeps his word. He is like a cheque book. As soon as a cheque is written, you can count on cashing it, and he doesn’t waste any time.”

Mr Wu was also not wasting any time by immediately setting his sights on Starwood. A regulatory filing on the company’s deal with Marriott reveals that an overseas company, identified as Anbang by a person familiar with the matter, made an non-binding offer to acquire Starwood last year. The original approach lacked any financing details, this person said, and Starwood’s executives were very concerned about Anbang’s ability to close the deal. Those concerns persist today, explaining Starwood’s decision to restate its support for Marriott’s offer on Monday.

This time, however, Anbang has enlisted support from investors including China’s Primavera Capital and JC Flowers & Co, the private equity outfit of US billionaire J Christopher Flowers.

Mr Wu is now going head-to-head for Starwood with Marriott, a company deeply connected to America’s business establishment. If he succeeds, it will mark China’s biggest upset ever in a foreign takeover battle.