BEIJING (Reuters) - China’s foreign exchange reserves unexpectedly fell below the closely watched $3 trillion level in January for the first time in nearly six years, though tighter regulatory controls appeared to making some progress in slowing capital outflows.

The dollar sign (R) is seen alongside the signs for other currencies above a currency exchange shop in Mongkok shopping district in Hong Kong, China, October 30, 2014. REUTERS/Damir Sagolj/File Photo

China has taken a raft of steps in recent months to make it harder to move money out of the country and to reassert a grip on its faltering currency, even as U.S. President Donald Trump steps up accusations that Beijing is keeping the yuan too cheap.

Reserves fell $12.3 billion in January to $2.998 trillion, more than the $10.5 billion that economists polled by Reuters had expected.

While the $3 trillion mark is not seen as a firm “line in the sand” for Beijing, concerns are swirling over the speed at which the country is depleting its ammunition, sowing doubts over how much longer authorities can afford to defend both the currency and its reserves.

Some analysts fear a heavy and sustained drain on reserves could prompt Beijing to devalue the yuan as it did in 2015, which could throw global financial markets into turmoil and stoke political tensions with the new U.S. administration.

While Beijing quickly downplayed the fall below the $3 trillion level, the breach could bolster China’s argument that it not deliberately devaluing its currency, ahead of the U.S. Treasury’s semi-annual report in April on currency manipulators.

To be sure, the January decline was much smaller than the $41 billion reported in December, and was the smallest in seven months, indicating China’s renewed crackdown on outflows appears to be working, at least for now.

Economists expect more forceful policing of existing regulatory controls after the latest slide, though China’s financial system is notoriously porous, with speculators quickly able to find new channels to get funds out of the country.

“With FX reserves below $3 trillion, we can expect capital controls as well as tightening yuan liquidity to continue, as the authorities try to avoid a further drawdown,” said Chester Liaw, an economist at Forecast Pte Ltd in Singapore, referring the central bank’s surprise hike in short-term interest rates on Friday.

While the world’s second-largest economy still has the largest stash of forex reserves by far, it has burned through over half a trillion dollars since August 2015, when it stunned global investors by devaluing the yuan.

The yuan CNY=CFXS fell 6.6 percent against a surging dollar in 2016, its biggest annual drop since 1994.

The crackdown is threatening to squeeze legitimate business outflows from China as well, with some European companies reporting recently that dividend payments have been put on hold and Chinese firms having a tougher time winning approval for overseas acquisitions.

“In their efforts to reduce outflows, the authorities have so far avoided contentious, high profile measures such as formally re-imposing restrictions on outflows or re-introducing

rules on the sale of U.S. dollar receipts by exporters, for fear of damaging the reputation of China’s reform process,” said Louis Kuijs, head of Asia Economics at Oxford Economics.

“Our analysis suggests, however, that they are likely to end up taking such steps eventually.”

COULD HAVE BEEN WORSE?

The drop in January’s reserves would have been worse if not for a sudden reversal in the surging U.S. dollar in January, some analysts said. The softer dollar boosted the value of non-dollar currencies that Beijing holds.

“Based on our calculation, the FX valuation effect alone would lead to a sizeable increase of reserves by US$28 billion,” economists at Citi said in a note.

However, despite tighter capital curbs and a bounce in the yuan, Citi estimated net capital outflows still intensified to nearly $71 billion in January from $51 billion in December.

Adding to the pressure, many Chinese may have exchanged yuan for dollars and other currencies to travel overseas during the long Lunar New Year holidays.

“Today’s FX reserve number suggests that the authorities are willing to trade a relatively stable yuan-dollar exchange rate for falling FX reserves because of financial stability concerns,” the economists at Citi added.

The yuan has gained nearly 1 percent against the dollar so far this year.

But currency strategists polled by Reuters expect it will resume its descent soon, falling to near-decade lows, especially if the U.S. continues to raise interest rates, which would trigger fresh capital outflows from emerging economies such as China and test Beijing’s enhanced capital controls.

The drop in reserves in January was mainly due to interventions by the central bank as it sold foreign currencies and bought yuan, China’s foreign exchange regulator, the State Administration of Foreign Exchange (SAFE), said in a statement.

But SAFE said that changes in China’s reserves were normal and the market should not pay too much attention to the $3 trillion level.

HOW LOW CAN THEY GO?

While estimates vary widely, some analysts believe China needs to retain a minimum of $2.6 trillion to $2.8 trillion under the International Monetary Fund’s (IMF’s) adequacy measures.

If the dollar’s rally gets back on track, fears of a yuan devaluation would likely spark more intense capital flight.

“The fact that China holds less than $3 trillion in reserves right now means that China has to rethink its intervention strategy,” said Zhou Hao, a senior emerging markets economist at Commerzbank in Singapore.

It does not make much sense to keep sharply draining reserves if market expectations of further yuan weakness are unlikely to change, he added.