Following the stake-sale, Blackstone has fallen to 52 per cent from a little over 60 per cent.
However, the buyer of the shares could not be ascertained immediately.
In April 2016, Blackstone had bought Hewlett Packard Enterprise's 60.5 per cent stake in Mphasis at Rs 430 per share and made an open offer at Rs 457 per share in 2016.
"Today's block was strategically executed to create more liquidity in the stock and enable high quality long-term investors to participate in the Mphasis growth story. Blackstone does not intend to sell any additional stake," the spokesperson said.
Shares of Mphasis closed 0.08 per cent higher at Rs 985.45 on BSE.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)