By Maitane Sardon

BlackRock Inc. said Wednesday that Scottish Widows, a U.K. pension provider, has allocated 2 billion pounds ($2.6 billion) of its pension portfolios to its new low-carbon fund.

The asset manager said it has launched a new ESG fund as part of its goal to help clients build sustainability into their portfolios. In January, BlackRock said it would put sustainability at the center of its investment strategy.

BlackRock said the Climate Transition World Equity Fund invests in companies that are "well prepared" for the transition to a low-carbon economy and has less exposure to companies that are "less equipped."

The fund will use a five-pillar framework looking at risks and opportunities in energy production, clean technology and management of energy, waste and water. BlackRock will score companies based on their management of the five pillars relative to other companies in the sector.

The fund won't invest in controversial and nuclear weapons and companies that breach the UN Global Compact. It will also exclude companies generating more than 5% of their revenues from tar sands, thermal coal or civilian firearms.

The asset manager said the fund launch reflects investors' growing demand for investment tools that incorporate assessments of climate change-related risks and opportunities.

Maria Nazarova-Doyle, head of pension investments at Scottish Widows, said offering customers more sustainable investment choices for their pension portfolios and challenging companies to behave more sustainably and responsibly is a central part of the pension provider's strategy.

Write to Maitane Sardon at maitane.sardon@wsj.com