BEIJING -- Reports based on millions of leaked documents say relatives of past and present Chinese officials, including the brother-in-law of current President Xi Jinping, opened overseas shell companies of the type that have sometimes drawn criticism. Previous reports by international media on the personal finances of Chinese leaders have drawn retaliation from Beijing, frequently through the blocking of media websites and a refusal to issue visas to their journalists.

Here's a look at two of the best-known investigations and their outcomes.

SENSITIVE TIMING: In the months before a 2012 once-in-decade power transfer in Beijing, both The New York Times and the Bloomberg News service published articles detailing the family wealth of incoming and outgoing Chinese leaders.

Bloomberg said then-Vice-President Xi's extended family, mainly his older sister Qi Qiaoqiao, her husband, Deng Jiagui, and Qi's daughter, Zhang Yannan, had investments in various companies, an 18 per cent stake in a rare earths firm with $1.73 billion in assets, and a $20.2 million holding in a technology company. The report said none of the wealth could be traced directly to Xi, his entertainer wife Peng Liyuan or their daughter, but it is widely believed that political influence and insider knowledge are factors in the building of such fortunes.

The New York Times said a review of corporate and regulatory records showed that relatives of then-Premier Wen Jiabao controlled assets worth at least $2.7 billion and hid that wealth through layers of partnerships and investment vehicles.

ANGRY RESPONSE: Xi did not respond publicly, but Wen reportedly issued a statement through a law firm denying the Times report. Chinese spokesmen issued furious denunciations, a reflection of the extreme sensitivity surrounding the private lives and personal finances of the Chinese leadership. The New York Times was threatened with a lawsuit, although no action appeared to be taken. Xi's brother-in-law, Deng Jiagui, told Bloomberg he was retired and that it was "not convenient" to discuss the family's investments.

Beijing blocked access to Bloomberg's website in China. The New York Times, which won a Pulitzer Prize for its coverage, also had its Chinese-language service blocked, alongside its English-language website, which had long been inaccessible inside China.

China often refuses to grant or renew visas to reporters whose work has angered the leadership. The New York Times suffered especially in the wake of its Wen report, with reporters denied permission to live in the country or enter for short-term assignments.

Xi later said foreign journalists must comply with Chinese laws while working in China and should examine themselves for why they had trouble obtaining visas.

"It's like a car that broke down halfway," Xi said at a news conference with visiting U.S. President Barack Obama in November 2014. "Maybe you should get off the car and see where it went wrong."