In the announcement, GPIF said "Such investments will be made throughout approximately 5‐year investment period the aggregate investment outstanding may reach up to 2.7 billion US dollar (280 billion Japanese yen) which accounts for 0.2% of the asset under management (129 trillion Japanese yen as of the end of December, 2013)".
GPIF also said "Infrastructures are classified as “international fixed incomes” in the policy asset mix and managed as a part of GPIF’s in‐house investment."
GPIF's official announcement can be found at:
(English) http://www.gpif.go.jp/en/fund/pdf/gpif_launches_infrastructure_investment_program.pdf
(Japanese) http://www.gpif.go.jp/topics/2013/pdf/gpif_launches_infrastructure_investment_program_ja.pdf
(English) http://www.dbj.jp/en/topics/dbj_news/2013/html/0000015061.html
(Japanese) http://www.dbj.jp/ja/topics/dbj_news/2013/html/0000015060.html
According to a Nikkei report, "The GPIF will earmark only 0.2% of its 130 trillion yen ($1.26 trillion) in assets under management for infrastructure investment, but suggested that the figure may increase. The fund will consider other partnerships as well as other investment areas, such as private equity and real estate, according to a senior official."