A year ago the Saudi sovereign investor Public Investment Fund (PIF) was a rising star among state-backed funds. : RIYADH/DUBAI (Reuters) - A year ago the Saudi sovereign investor Public Investment Fund (PIF) was a rising star among state-backed funds. It poured billions of dollars into the SoftBank technology fund of Japanese tycoon Masayoshi Son and the infrastructure vehicle of U.S. private equity firm Blackstone, and was building a war chest for overseas deals.