The size of the drop was second only to the $107.9 billion fall in December, the largest monthly decline on record. The central bank has intensified efforts to prop up the yuan after it staged a surprise devaluation in early August.
China's reserves remain the world's largest despite losing around $420 billion in the last six months. In 2015, they fell by $513 billion, the largest annual drop in history.
The country's foreign exchange regulators said on Feb. 4 that trade and investment had caused $342.3 billion of the drop in reserves in 2015, while currency and asset price changes caused another $170.3 billion fall.
Officials said the fall had been further exacerbated by a rush by local firms to repay foreign debt and increased dollar buying by local residents as the yuan fell.
Capital outflows have gained momentum since the yuan's August devaluation, fanned by concerns about China's economic slowdown and expectations of U.S. interest rate rises.
"Monetary easing is highly needed amid economic slowdown, but the capital outflow will naturally tighten the monetary policy," Hao Zhou, senior emerging markets economist at Commerzbank in Singapore, said in a note after the data.
"In the meantime, to prevent the currency from a fast depreciation, the PBOC (People's Bank of China) will have to sell its FX reserves, which will tighten the liquidity."