RIYADH- Saudi Arabia's Public Investment Fund (PIF), the country's main sovereign wealth fund, will contribute $20 billion to a $40 billion fund with U.S. private equity firm Blackstone, its managing director said on Tuesday.

The fund will invest in "conventional economy" including sectors such as medical care and education, Yasir Al Rumayyan said at a major investment conference in the capital Riyadh.

PIF and U.S. private equity firm Blackstone announced in May the execution of a memorandum of understanding for the launch of an infrastructure investment vehicle with an anchor $20 billion contribution by PIF.

As part of Saudi Arabia's economic reforms announced last year, the Saudi government plans to expand PIF, founded in 1971, to finance development projects in the country.

PIF expects to create over 20,000 jobs by 2020 through its projects, Al Rumayyan also said on Tuesday.

"With our short term plans, we will have more than 20,000 jobs in 2020 and beyond it's going to be a lot more."

The Public Investment Fund has a portfolio made up of listed holdings, but also unlisted equity investments, international investments, real estate, loans, bonds and sukuk.

(Reporting by Reuters team; Editing by Samia Nakhoul) ((Davide.Barbuscia@thomsonreuters.com; +971522604297; Reuters Messaging: davide.barbuscia.reuters.com@reuters.net))