Unacademy last picked up $110 million from Facebook and PE firm General Atlantic in February, at a valuation of $510 million.
Existing investors will also participate in the latest equity funding round, the sources said without sharing further details.
Sequoia Capital, Nexus Venture Partners, Steadview Capital and Blume Venture have been early backers of the firm.
Unacademy did not respond to ET’s emails seeking comment. A SoftBank spokesperson said the firm will not comment on market “speculation”.
The fundraising will mark the first investment in an Indian firm by SoftBank since December, when it had backed eyewear retailer Lenskart.
The famed technology investor has over the past year slowed down new bets globally, cutting fewer cheques following the IPO debacle at portfolio firm WeWork.
SoftBank Vision Fund’s other big Indian portfolio companies such as budget hotels chain Oyo and digital payments platform Paytm have also been under the scanner due to mounting losses.
News website moneycontrol.com was the first to report SoftBank’s plans to invest in Unacademy on Friday.
The likely funding from SoftBank comes after Unacademy saw a spike in online learners in the days following the Covid-19 outbreak.