Section 141(3)(d)

As per literal interpretation of rule 10, sub rule 1 which clearly express relative of applicant  may hold the security interest only in the concern company in which proposed applicant wants to appoint. 

In your query relative of applicant (auditor) shall not allow to hold security interest in the holding Co., subsidiary Co. Or associate Co. 

However as per rule 10 sub rule 2 and 3 which allow such holding by relative subject specified limit as mention in rule 10 itself. 

holding share of upto FACE VALUE OF RS 1,00,000 /- in company , its holding , subsidiaries or associates .