The biggest backers of SoftBank Group Corp.'s gargantuan Vision Fund are reconsidering how much to commit to its next investment vehicle as an oversized bet on flexible workspace provider WeWork sours.

Saudi Arabia's Public Investment Fund, which contributed $45 billion to the $100 billion Vision Fund, is now only planning to reinvest profits from that vehicle into its successor, according to sources familiar with the talks.

Abu Dhabi's Mubadala Investment Co., which invested $15 billion, is considering paring its future commitment to below $10 billion, the sources said, asking not to be identified in disclosing internal deliberations.