Japan's foreign-exchange reserves totaled $846.90 billion at the end of December, up $3.63 billion from a month earlier and marking the second-highest level on record, the Finance Ministry said Wednesday.
The increase stemmed from interest income and valuation gains on holdings of U.S. Treasuries and other foreign securities, the ministry said.
The tally was the second-biggest on record, following $847.77 billion at the end of last August.
Japan had $706.26 billion in foreign securities as of Dec. 31, up from $702.08 billion a month earlier.
Foreign currency deposits stood at $122.55 billion, up from $122.19 billion.
Of the deposits, $7.87 billion was held in foreign central banks and the Basel-based Bank for International Settlements, $39.42 billion in Japanese banks and $75.27 billion in foreign institutions.