The court asked them to be present on June 4.
The summons was issued after the court took cognisance of the supplementary chargesheet filed against Sabitha Reddy and Kripanandam by the CBI on April 9.
According to the CBI, the two sanctioned OMC's proposal for mining lease by giving it a preferential treatment while rejecting applications of other firms.
Others named by CBI in its chargesheets in the case include former Karnataka minister and OMC owner Janardhan Reddy and his brother-in-law B V Srinivas Reddy (both now in jail), IAS officer Y Srilakshmi and K Mehfuz Ali Khan, the personal assistant of Janardhan Reddy.