Dear Madhu,
I have clearly stated about Superannuation Scheme for employees and introduced through I.R.D.A. and works under IT act Rules 89 to 91 deal with this aspect and 15% of Basic+DA is a formula.
Pls read the below explained on contributions;
82.6 Rules 87 and 88 specify the limits upto which ordinary annual contributions and initial contributions respectively are permissible.
82.6-1 Ordinary annual contributions - The ordinary annual contributions in respect of any employee by the employer should not exceed :
(27% of annual salary) minus (Employer’s contribution to any provident fund, whether recognised or not, for that year).
Illustration : Suppose the employee’s annual salary is Rs. 30,000, and the employer is contributing Rs. 3,000 to the provident fund account of that employee, the contribution to the superannuation fund of that employee should not exceed Rs. 8,100 (27% of salary) minus Rs. 3,000, i.e., Rs. 5,100.
*The statutory background for Superannuation scheme;
82.1 Section 2(6) of the Act defines an ‘approved superannuation fund’ as ‘a superannuation fund or any part of a superannuation fund which has been and continues to be approved by the Chief Commissioner or Commissioner in accordance with the rules contained in Part B of the Fourth Schedule’.
Further, LIC of India has this Superannuation scheme that one can visit P&GS department of LIC of India and understand in detail.