Mumbai, Oct 26 : Premji Invest , the investment arm of Wipro Group chairman Azim Premji, today announced the acquisition of a significant minority stake in Hygienic Research Institute, one of the largest home grown hair-care- focused FMCG companies. A statement from the Mumbai-based institute however did not share the investment details such as the quantum of stake being sold to Premji Invest and the price at which the sale has been concluded.