The detention of Mr. Wu is likely to reverberate through business circles in China and the United States.
Anbang, which claims to have almost $300 billion in assets, had recently been on a worldwide buying spree, and Mr. Wu counted Wall Street executives like Stephen A. Schwarzman as among his business partners in the United States.
The Caijing article said Mr. Wu was detained as part of a Chinese government investigation into Anbang. The two people who confirmed that Mr. Wu had been detained asked for anonymity because they were not authorized to speak to the news media.
Anbang is also a major issuer of speculative wealth management products, which have attracted a tidal wave of money from Chinese investors. Mr. Wu’s detention follows a move last month by China’s insurance regulator to bar the company from offering new insurance products for three months as part of a wider clampdown. The regulator said at the time that it was taking disciplinary measures against the company over the improper sale of insurance products.
It was not clear on Tuesday what would happen to Mr. Wu. Some executives caught up in the government’s crackdown on corruption in the financial sector, which began last year, have vanished for a few days only to reappear, back in charge of their companies. Others, like Mr. Xiao, have been held for months in undisclosed locations without any charges being publicized.
Xu Ming, a billionaire caught up in a 2012 political scandal, vanished and died in prison in late 2015 at 44, according to a report in one Chinese government-owned newspaper in Hong Kong.
Sterling political connections on both sides of the Pacific Ocean might have worked to Mr. Wu’s advantage in his business dealings. He married a granddaughter of Deng Xiaoping, China’s paramount leader in the 1980s and in November met with Jared Kushner, Mr. Trump’s son-in-law and a top adviser, in a bid to buy a stake in a Manhattan office building partly owned by Mr. Kushner’s family company. The deal was eventually abandoned after media coverage that highlighted a perceived conflict of interest. Mr. Kushner’s purview at the White House includes relations with China.
Anbang has taken the money it raised from Chinese savers and invested much of it abroad. Last year, Anbang spent more than $6 billion for a collection of luxury hotels across the United States. The seller of those hotels was the Blackstone Group, whose chairman and chief executive, Mr. Schwarzman, is one of Mr. Trump’s closest business advisers.
In a separate effort, Anbang offered more than $13 billion for Starwood Hotels and Resorts before abandoning its bid early last year after media scrutiny of its opaque ownership structure.
China’s insurance sector has been in turmoil in recent months. In April, anti-corruption investigators announced that they were focusing on the insurance sector and specifically, the country’s top insurance regulator. Xiang Junbo, the chairman of China Insurance Regulatory Commission, was later removed from office after the government placed him under investigation for “severe violations of discipline.”
Mr. Wu’s detention comes at a politically sensitive time in China. The ruling Communist Party is set to convene a leadership meeting this year that will pick a new generation of top officials, and the party puts the preservation of stability — both financial and political — at a premium in the months ahead of the conclave, held once every five years.
“The framing question here is, has he been behaving badly by Chinese standards?” asked Derek M. Scissors, a resident scholar and China economist at the American Enterprise Institute. “If it’s just him doing something the party doesn’t like, it doesn’t matter. The question is whether the whole firm has been used to do things the party doesn’t like.”
In its statement, Anbang said that the company would continue to operate as usual without Mr. Wu. But it is unclear if Anbang can still pursue its global ambitions if Mr. Wu does not return to the helm.
Questions about Anbang’s internal workings and political ties have dogged the company in recent years. Even a cursory examination of its shareholding structure shows a company that is remarkable in its opacity.
Founded in 2004 by Mr. Wu and several other businessmen in the eastern Chinese city of Ningbo, the company boasted remarkable political connections from its inception. One of its early business partners was Chen Xiaolu, the son of a People’s Liberation Army marshal from the first decades of Communist rule. The board once included the son of a former prime minister and a top trade official who led China’s negotiations into the World Trade Organization.
Anbang, which originally focused on car insurance and was partly owned by a state-owned automaker, expanded quickly and moved its headquarters to Beijing.
While Anbang’s growth was easy to track, its ownership was not. Last year, an investigation by The New York Times into the company found that 35 of its 39 shareholders, all companies, were once owned by Mr. Wu or his relatives, Deng’s granddaughter or Mr. Chen.
While many of the companies are owned at least in part by Mr. Wu’s family members near Wenzhou, a heavily Christian city south of Ningbo, the trail to identify other current owners ended at times at mail drop boxes and empty offices, The Times found.
That unusual structure drew the attention of insurance regulators in New York, who asked Anbang last year to provide more information before it signed off on a proposed $1.6 billion acquisition of a Des Moines-based life insurer, Fidelity & Guaranty Life. That deal, like those for Starwood and the Kushners’ Fifth Avenue office tower, fell through.
Still, Anbang’s opaque structure did not stop the company’s $6.5 billion acquisition of a portfolio of luxury hotels from Blackstone. The deal, with the exception of a hotel located next to a naval base, was cleared by the Committee on Foreign Investment in the United States, or Cfius, as was the purchase of the Waldorf Astoria.
Mr. Wu made much of his relationship with Mr. Schwarzman, who now heads Mr. Trump’s business advisory council. During a question–and–answer forum at Harvard University in 2015, Mr. Wu described Mr. Schwarzman as a good friend. A spokeswoman for Blackstone declined to comment.
Later on Wednesday in China, the Caijing article and other accounts of Mr. Wu’s detention had been removed from the internet.
An earlier version of this article, in describing Wu Xiaohui’s political ties, misstated his wife’s relation to Deng Xiaoping, the former leader of China. She is Deng’s granddaughter, not daughter.