Japan aims to raise the ratio of unlisted shares, real estate and other alternative investments in the portfolio of the Government Pension Investment Fund, the world's largest pension fund, the Nikkei said on Sunday. Finance Minister Satsuki Katayama, who has been trying to boost the weak yen, sparked a jump in the currency and government bond prices on Friday by saying the government aimed to steer the $1.8 trillion GPIF and other state pension funds to "substantially" increase investments in domestic assets.