Angola’s sovereign wealth fund increased its investment in private equity firms operating in the country and across sub-Saharan Africa to more than half of its $5 billion, the fund said in a 2015 update.

A sovereign wealth fund is a state-owned investment fund investing in real and financial assets such as stocks, bonds, real estate, precious metals, or in alternative investments such as private equity fund or hedge funds.

The Angolan fund, which is also know by its Portuguese name Fundo Soberano de Angola (FSDEA), said 58 percent of its $4.7 invested assets were in PE funds that focused on infrastructure, real estate, timber, mining, health care and mezzanine capital, Bloomberg reported.

According to FSDEA website, it had a 34 percent of its assets invested in unlisted securities and debt in 2014.

The fund’s chairman Jose Filomeno dos Santos, who is also the son of Angola’s long-serving President Jose Eduardo dos Santos, said that PE firms they has invested in “focused on domestic and regional business opportunities”.

“These equity investments will position FSDEA’s capital ideally to generate new sources of revenue for Angola, as well as to support the development of new industries, beyond the crude oil production and trading,” he said in a statement quoted by Reuters.

FSDEA, which has about 20 percent of its investments in infrastructure projects in Angola and Kenya, said it had cut its exposure in fixed income to less than a quarter of its assets.

In 2014, it has 56 percent if its holdings in debt securities, mostly in North American and European markets.

The Angolan sovereign fund is wholly owned by the state and was established in 2012 to help invest the county’s oil revenue and diversify the economy from any shocks in the global crude market.

The country, which is Africa’s second largest oil producer after Nigeria, has been facing financial challenges due the impact of low oil prices.

African sovereign wealth funds are emerging to save and invest resource revenue in resource rich countries, which have come under heavy financial constraints after crude prices more than halved globally since the last quarter of 2014.

Other countries that have set aside revenue for a rainy day include Botswana, Mozambique and Zimbabwe, while East African nations of Tanzania, Rwanda and Kenya have shown intend to do so too.