Established in December 1993, the trust uses income and capital from its Trustpower holding to benefit its 56,000 Trustpower account holders in Tauranga City and Western Bay of Plenty.
It pays an annual distribution direct to consumers and also gives grants to the local community.
The sale will allow it to maintain a cornerstone shareholding in the power company while diversifying its investment.
"It's purely a decision based on diversifying our investment portfolio," Wayne Werder, general manager of the trust, told BusinessDesk.
"Trustees are working through reinvestment options, which is likely to be some form of diversified portfolio.
"We have maintained our 26 per cent interest in Trustpower which maintains our influence in the company," Werder said.
"There's no plans to sell any more shares. Our Trust is still very much committed to Trustpower."
The Consumer Trust is hopeful the sale of its shares will boost liquidity in Trustpower stock, more than half of which is owned by infrastructure investor Infratil.
See Trustpower's statement announcing the sale here: