Trust banks were net buyers of Japanese stocks last week for a sixth successive week, exchange data showed on Thursday, indicating that pension funds may be buying Japanese equities.

Net buying of stocks by trust banks, which manage corporate pension trusts and national pension fund trusts, stood at 28.3 billion yen last week, data from the Tokyo Stock Exchange showed.

It was the sixth consecutive week of net buying.

"The figure doesn't tell who bought the stocks, but we can speculate that pension funds such as the GPIF might have bought Japanese equities," said Jun Yunoki, strategist at Nomura Securities.

Under pressure from the government of Prime Minister Shinzo Abe to shift money into higher-risk assets and out of low-yielding Japanese government bonds, the GPIF pension fund plans to boost the weighting of domestic stocks to more than 20 percent from a current target of 12 percent.