As Anbang Insurance Group Co. Chairman Wu Xiaohui hunts for purchases on his global deal-making spree, he often relies on the same tactics: swoop in at the last minute or pre-empt any other bidders.

The Chinese owner of New York's Waldorf Astoria hotel this month made a last-minute, $12.9 billion offer for Starwood Hotels & Resorts Worldwide Inc.

Anbang's attempt to derail an agreement by Marriott International Inc. to purchase the owner of Sheraton, Westin and W hotels, just two weeks before a shareholder vote, followed at least three other cases where Wu sought to upend a deal process.

Anbang said in an e-mailed statement this week that all its acquisitions are friendly, and it backs out whenever there is opposition from stakeholders.

"Our investments are in fact the final results of numerous project analysis and judgments made by our international investment team," the statement said.

In addition, all of Anbang's internal decisions are made by investment professionals, and deals are made only after weighing the costs and benefits, the statement said.

However, the deals show how Anbang's Wu seeks to play by his own rules as he builds an insurance, finance and property empire with assets spanning Belgium, the Netherlands, South Korea and the United States.

His first trophy purchase, a 2014 deal for the Waldorf Astoria, came from a pre-emptive $1.95 billion bid before an auction could get underway.

"It's definitely not the so-called corporate style, with investment banking teams and rounds of due diligence," Linda Sun-Mattison, an analyst at Sanford C. Bernstein & Co., said by phone. "The chairman knows what kind of assets he wants, what kind of characteristics he likes, and he does it."

The Chinese company's deal-making style could form part of the deliberations for the Starwood board, which will balance the competing proposals.Marriott's bid mostly consists of stock, while the Anbang consortium has offered $76 a share in cash. Starwood can hold discussions with the Anbang-led consortium through March 17.

A purchase of Starwood would bring the amount of acquisitions by Anbang over the past two years to about $27 billion, data compiled by Bloomberg show. Wu typically avoids turning to outside bankers, instead opting to negotiate most deals himself, according to people who have dealt with him.

"Something like this, coming in at the last minute, is very rare," said Steven Lam, an analyst at Bloomberg Intelligence in Hong Kong. "You don't see that strategy in any typical M&A."

One of Anbang's earliest major deal attempts outside mainland China was its pursuit of family-run Hong Kong lender Wing Hang Bank beginning in 2013.

The Chinese insurer continued contacting the seller and arguing the merits of its proposal even after Singapore's Oversea-Chinese Banking Corp. was granted exclusive rights to negotiate a deal.