Two of the biggest investors in SoftBank's original Vision Fund are debating whether to significantly cut back on their commitments to a planned second one, Bloomberg reported.

Saudi Arabia's Public Investment Fund put $45 billion into SoftBank's original Vision Fund, but only plans to commit its profits from that investment into the second fund, according to the report.

Abu Dhabi's Mubadala Investment is considering reducing its stake in the second Vision Fund to less than $10 billion, from the $15 billion it put into the first one, Bloomberg reported.

The investors' debates over their commitments to the second Vision Fund come as the original fund is reportedly down $600 million on its stake in Uber and as it prepares for a big drop in the value of its WeWork investment as public investors have soured on that company's planned public offering.

Read all of Business Insider's WeWork coverage here.

SoftBank CEO Masayoshi Son may have trouble raising a second Vision Fund after all.

With Japanese conglomerate's original $100 billion fund struggling with two of its highest profile investments, two of its biggest investors — Saudi Arabia's Public Investment Fund and Abu Dhabi's Mubadala Investment — are re-evaluating how much money they'll put into a planned follow-on fund, Bloomberg reported Monday. Both are considering significantly reducing their investment from the amounts they committed to the first fund, according to Bloomberg.

The Saudi investment vehicle committed $45 billion to the original Vision Fund, making it the fund's biggest backer. It now plans to invest only its profits from the first Vision Fund into the second one, Bloomberg reported.

Mubadala was the second largest outside backer of the Vision Fund, committing $15 billion to it. The Abu Dhabi company is considering limiting its investment in the new fund to less than $10 billion, according to Bloomberg.

A Mubadala representative told Bloomberg the company is still discussing its potential stake in the new fund and denied that it had yet made a decision on the when or how much to commit. A representative for the Public Investment Fund declined comment to Bloomberg.

SoftBank representatives did not immediately respond to an email from Business Insider seeking comment.

Read this: Venture investors still aren't sure what to make of SoftBank's $100 billion Vision Fund. Depending on who you ask, they're either rooting for it, or gleeful that it's struggling with WeWork and Uber.

Uber and WeWork have given the first Vision Fund a black eye

The investors' apparent trepidation over the new Vision Fund comes amid some high-profile setbacks for the original. SoftBank's giant fund has reportedly lost some $600 million on its investment in Uber, thanks to that company's disappointing public offering and the subsequent decline in Uber's stock price.

Meanwhile, WeWork, in which SoftBank has invested $10.65 billion, is struggling to attract investors for its own public offering. Last week, the company was reportedly considering going public with a market capitalization of as little as $10 billion — less that a quarter of the $47 billion valuation SoftBank conferred on it with a January investment.

Earlier this month, many venture capital experts told Business Insider they had faith SoftBank would still be able to find investors for its second Vision Fund, despite its troubles with Uber and WeWork.

SoftBank has already received commitments from Apple and Microsoft, among other investors, for the new fund.

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