A group of foreign institutional investors (FIIs) that together own more than 10% of Tata Motors has written to the board expressing concerns about the possibility of Tata Sons being given preferential access to strategic information ahead of other investors, according to persons directly aware of the matter. The letter makes no reference to the recent sacking of Cyrus Mistry as chairman of Tata Sons in a boardroom putsch that saw Ratan Tata return to the helm of the holding company . But its despatch appears to have been sparked by revelations made by Mistry -who remains chairman of Tata Motors -defending his record and blaming decisions by Ratan Tata for the group’s performance.