China’s total debt is probably billions of dollars more than the official data show and the Chinese economy is so addicted to credit that any effort to tighten the money flow is likely to result in severe disruptions, according to Goldman Sachs.

Given widespread concerns about the reliability of data released by the government, Goldman analyst MK Tang decided to follow the money trail to get a better picture of China’s debt burden. What he concluded is that the country’s debt in 2015 was about 6 trillion yuan ($913 billion) more than the figure announced by the People’s Bank of China.

The findings come at a time when investors have become increasingly worried about China’s mounting debt as the country continues to rely on borrowed money to prop up its economy.

“We find that a substantial amount of money was created last year, evidencing a very large supply of credit, to the tune of 25 trillion yuan — 36% of 2015 GDP. This is about 6 trillion yuan, or 9 percentage points of GDP, higher than implied by total social financing data,” said Tang in a report.

Total social financing is a broad measure of credit in the economy, but Tang believes it is not comprehensive enough as it excludes bond-swap programs and shadow loans, which do not show up on financial institutions’ balance sheets.

What Tang decided to do was to track where households and corporations invest their money, which he felt was broad enough to reflect the diversification in lenders but still narrow enough to avoid double counting.

“In trying to follow the money flow more systematically as in our exercise, it seems clear that there was a lot of money created and circulating around amongst households and corporates relative to what the TSF shows,” he said.

Tang also discovered that the gap between his data and official government figures started to widen in the second quarter of 2015, which coincided with the central bank’s shift to loose monetary policy in response to an economic slowdown.

“The experience in 2015 suggests that the economy’s dependence on credit has deepened significantly and that it likely needs sizeable flow of credit on a persistent basis to maintain a stable level of growth,” said Tang.

The analyst also expressed concerns over whether China can sustain its debt burden, as well as the lack of transparency in the financial system given the growth in shadow banking, which raises concerns about failure in regulatory oversight.

But the bigger issue is that it interferes with identifying potential stress points and predicting how a possible contagion may unfold, he said.

Meanwhile, Zhiwei Zhang, chief economist at Deutsche Bank, noted that the Chinese government started to take steps to rein in credit growth last month, leading to a decline in corporate bond issues.

“We think the government’s strategy is to contain the buildup of leverage within the financial sector and bolster direct financing through policy banks,” said Zhang.

Tighter credit control is likely to lead to weaker property prices and slower economic growth in the second half of the year as well as pressure the Chinese yuan.

“This could increase incentives for domestic liquidities to seek overseas investment opportunities and push up capital outflows,” he said.

Zhang projected the yuan USDCNY, to decline to 7 per U.S. dollar by the end of the year from 6.57 currently.

China’s foreign exchange reserves fell by $27.93 billion to $3.192 trillion in May after rising $17 billion in March and April.

The resumption in outflows is not cause for alarm, according to Julian Evans-Pritchard, China economist at Capital Economics.

However, with the U.S. Federal Reserve expected to raise interest rates soon, it could trigger another round of outflows which could further strain the yuan, he said.