The Mumbai Interbank Offered Rate (MIBOR) is calculated everyday by the National Stock Exchange of India (NSEIL) as a weighted average of lending rates of a group of banks, on funds lent to first-class borrowers. 26. It is the interest rate at which banks can borrow funds, in marketable size, from other banks in the Indian interbank market. 27. The MIBOR was launched on June 15, 1998 by the Committee for the Development of the Debt Market, as an overnight rate.