The reserves were enough to pay for four months of the country's imports, a month more than the minimum set by the International Monetary Fund, A.F.M. Asaduzzaman, spokesman of Bangladesh Bank, said.
Remittances from Bangladeshis working abroad have picked up, ahead of the Eid-al Adha festival later this month, officials said.
Money sent home by about eight million citizens abroad is a key source of foreign exchange alongside garment exports, which account for 80 percent of the total export earnings of around $25 billion a year.
A majority of Bangladesh expatriates is employed in the Middle East and almost 60 percent of the remittances come from there.
The central bank has purchased $1.7 billion from commercial banks since July to hold down the value of the local currency, against the US dollar, a central bank official said.
"We support this intervention as it will encourage both the exporters and expatriates as these two sectors are the mainstays of our economy," Shah A Sarwar, Managing Director of the private Trust Bank Limited, said.