The study in the regular quarterly report by the central banks' central bank also said that capital flight from the yuan, also known as renminbi, had tended to be about the repayment of dollar-denominated debt by Chinese companies rather than widespread sales of mainland assets.
That might point to a reduction of the pressure that has forced China to use hundreds of billions its huge foreign currency reserves to fend off deeper devaluation of the currency.
The BIS data, taking in the third quarter of 2015 and a partial reading of the fourth quarter, showed that companies and rich Chinese individuals exchanged yuan held in offshore locations such as Hong Kong and Singapore for dollars as they lost faith in the currency.
Of $175 billion in cross-border capital flows out of China in the third quarter, $40 billion was because of such reductions in offshore deposits. Banks in those jurisdictions responded by drawing down deposits with mainland banks, leading to a total capital outflow of $80 billion.
With a further $41 billion in net repayment of foreign currency debts by Chinese companies, both cross-border and within China, that brings the total of money flowing out in these three forms to $121 billion, BIS said.
"The combination of reduced offshore renminbi deposits and Chinese firms’ paydown of foreign currency debt reflects the unwinding of carry trades and explains the downward pressure on China’s currency," said Hyun Song Shin, BIS Economic Adviser and Head of Research.
"It also shows why the offshore renminbi rate trades at a discount to the onshore rate during periods of stress."
However, the fourth-quarter numbers and those for the start of 2016 are likely to prove more important for the investors who have bet against the yuan since a surprise devaluation last summer.
People's Bank of China reserves have been falling by about $100 billion a month since November.
BIS said that Hong Kong Monetary Authority data on cross-border claims on Chinese non-bank businesses showed an acceleration of net outflows in October and November and a faster contraction in onshore net foreign currency loans, by $29 billion.
(Editing by David Goodman)
By Patrick Graham
