In the high-profile refund case involving an estimated Rs 24,000 crore payment to over three crore investors, Sahara Group's Chief Subrata Roy and other top executives have been summoned for personal appearance tomorrow before the market regulator SEBI. The summons for personal appearance of Roy and three other directors of two Sahara firms were issued by SEBI to examine them for ascertaining details of their personal assets, as also the investments and assets of the companies, to move ahead with sale of immovable assets for realization of money to be refunded to the investors.