Using individual bidder data from the Eurosystem’s liquidity providing tenders for the pre-crisis period, we investigate banks’ joint bidding behaviour in Main Refinancing Operation (MRO) and Longer Term Refinancing Operations (LTRO). The Eurosystem’s instrument to manage its operational target are collateralized refinancing operations of two different maturities: short term money with a maturity of one week is auctioned weekly in MROs while term money with a maturity of three months is auctioned once a month in LTROs. Via adjusting the amount of loans given to the banks, the ECB can steer... liquidity in the overnight interbank market and the overnight interest rate. While research has investigated bidding behavior for MROs and LTROs separately, it has so far not explicitly focused on the interdependencies of joint bidding plans in these two operation types. We contribute to this literature by directly addressing this gap. This is the first paper which derives and formulates hypotheses about how the sequence of operations might affect bidding behavior in ECB liquidity auctions, and brings these tests to the data in an otherwise standard econometric framework. As theoretical auction literature has shown, auction participants usually take a longer sequence of operations into account when deciding about their bidding plans. In other words, banks consider bidding in the MROs and LTROs as a joint optimization problem and do not develop their bidding plans in isolation only for the MROs. To reflect this, we test whether banks bid differently in the MROs before and after the LTROs. More specifically, we first test whether banks bid in general at lower rates in the MRO before the LTRO. Furthermore, we hypothesize that banks which plan to bid in the MRO and LTRO will bid at even lower rates. This is because in the sequence of operations, the MRO takes place shortly before the LTRO. Hence, banks can split their bids between two operations and make up for a potential shortfall within a short period of time. Second, we test whether banks bid at higher rates after the LTRO. The motivation underlying this question is that the two preceding operations leave potentially more banks with a liquidity situation below their expectations. While data gaps do not allow for a direct test of this hypothesis, proxies for banks’ net demand confirm this conjecture. Hence, those bank have an incentive to bid at higher rates in order to make up for the liquidity shortfall.