Shapoor Mistry, chairman of Shapoorji Pallonji (SP) Group, has sought around Rs 25,000 crore from Tata Sons over the next 24 months for part of the stake held in the principal holding company of Tata group, people familiar with the matter said. SP Group owns an estimated 18.37% of the unlisted Tata Sons and has been exploring ways to monetise about 7% of its holding. Mistry has written to Tata Trusts chairman Noel Tata with the proposal, the people said. It's expected to be discussed by Tata Sons executives as the two sides seek a resolution to the matter, they added.