Government liabilities are classified as debt contracted against the Consolidated Fund of India (defined as Public Debt) and liabilities in the Public Account, called Other Liabilities. Public debt is further classified into internal and external debt. Internal debt consists of marketable debt and non-marketable debt. Government dated securities and treasury bills, issued through auctions, together comprise marketable debt. Treasury Bills issued to state governments and select central banks, special securities issued to National Small Savings Fund (NSSF), securities issued to international financial institutions, etc. are part of the non-marketable internal debt. External Debt refers to money borrowed from a source outside the country. External debt has to be paid back in the currency in which it is borrowed. Other Liabilities include liabilities on account of Provident Funds, Reserve Funds and Deposits, Other Accounts, etc.