Japanese investors became less enthusiastic about buying foreign bonds last year on growing concern about rising U.S. Treasury yields.

Japanese investors' net purchases of mid- to long-term foreign bonds nosedived 94.6% on the year to 1.1 trillion yen ($9.9 billion) in 2017, the Finance Ministry said Friday, marking the first annual decline in four years.

Institutional investors such as banks and life insurance companies had actively pursued foreign bonds in search of higher returns, finding few alternatives in Japan, where interest rates remained extremely low.

But the November 2016 election of Donald Trump as U.S. president sent the 10-year Treasury yield shooting up from around 1.8% to almost 2.6% in just over a month, and the yield stayed above 2% throughout 2017. Any investors holding onto Treasurys during the yield surge would have incurred significant losses as prices tumbled.