China's foreign exchange reserves dropped by $99.5 billion from December to $3.23 trillion at the end of January, the central bank said Sunday.
The decrease was milder than the decline of $107.9 billion registered in December, the sharpest monthly fall on record.
Zhou dismissed rumors that China will increase foreign exchange control. The rumors even involve control of trade accounts, which is absurd, Zhou said, claiming rumors are fabricated to create panic and benefit speculators.
China allowed renminbi convertibility on the trade accounts nearly two decades ago, but almost all capital account transactions in the mainland remain under varying degrees of control. Going by IMF classifications, 37 of 40 capital account items are already fully or partly convertible in China, leaving only three unconvertible.
The central bank will upgrade its macro prudential policy framework, an approach to financial regulation aimed at reducing systemic risks, according to Zhou.
The new mechanism, macro prudential assessment, will take into consideration seven aspects when evaluating the financial system to prevent systemic risks and improve counter-cyclical adjustment, the PBOC said in a statement at the end of 2015.
The capital adequacy ratio, a measure of an institution's ability to cushion loan risks, will be the core of the assessment, said the PBOC.
While guarding against "systemic risks in the economy, China should prevent "cross infection" between the stock, debt and currency markets, Zhou said.
China's economy grew by 6.9 percent year-on-year in 2015, its lowest annual expansion in a quarter of a century.
However, foreign direct investment into the Chinese mainland continued to grow steadily in January despite slowing overall growth, the Ministry of Commerce said on Monday.
FDI, which excludes investment in the financial sector, rose 3.2 percent year on year to $14.1 billion last month, with investment in the service sector taking the lion's share.