The bank must also co-operate within the EU and internationally with third bodies and entities. Finally, it contributes to maintaining a stable financial system and monitoring the banking sector. The latter can be seen, for example, in the bank's intervention during the subprime mortgage crisis when it loaned billions of euros to banks to stabilise the financial system. In December 2007, the ECB decided in conjunction with the Federal Reserve System under a programme called Term auction facility to improve dollar liquidity in the eurozone and to stabilise the money market.