SEBI has issued a circular CIR/IMD/FIIC/11/2013 dated July 31, 2013 regarding the utilisation period for Government Debt limits.
In accordance with the said circular, FIIs/QFIs shall be permitted to utilise the debt limits allocated to them in each monthly auction till the 17th day of the succeeding month. Any unutilised limit as on the 18th of each month would get auctioned on the 20th of each month, in terms of SEBI circular CIR/IMD/FIIC/8/2013 dated June 12, 2013
The circular is attached here for reference.