 In this paper, we analyze the relationship between financial stability and asset price bubbles. What distinguishes our paper from existing research is that we are taking the analysis to a microeconomic level, looking at individual banks rather than macroeconomic aggregates. We know from the literature that some financial bubbles lead to severe financial crises, but others don't. And we want to better understand where this comes from. And so in the end, our research question is, what is the relationship between asset price bubbles and systemic risk when looking at the bank and video level? We are facing two challenges. We first have to identify financial bubbles and then we have to measure systemic risk at the bank level. In order to identify financial bubbles, we are using the BSADF test, which is a very powerful test in order to detect financial bubbles by looking for explosive behavior in the price series. When measuring systemic risk, we are using the DeltaCova, the Delta Conditional Value at Risk, and it measures the contribution of individual banks to the system's systemic risk. In the next step, we are then relating our measure of systemic risk with our measure of financial bubbles and we are asking how this relationship depends on bank characteristics on the one side and bubble characteristics on the other. First we can confirm that there actually is an increase in systemic risk in times of financial bubbles and what is interesting is that we find such an increase already during the boom phase of the financial bubble. Of course, what interests us most is the heterogeneity across banks and across bubbles. We find that a main driver of the increase in systemic risk during financial bubbles is bank size. Large banks have much larger systemic risk contributions than smaller banks. In addition, we find that loan growth matters and maturity mismatch matters. When it comes to bubble characteristics, we find that especially during the boom phase of the bubble there is a clear relationship between the increase in systemic risk and the size and the length of a bubble. So, the longer a bubble has been around and the bigger it is, the larger is the increase in systemic risk. We know from economic history that financial bubbles can be extremely harmful and therefore of course we want to understand what to do about them. Our results suggest that it may make sense to tackle bubbles early on because what we saw is that systemic risk already increases quite substantially during the boom phase of the bubble. Moreover, we have seen that there is a lot of heterogeneity across the banks and this seems to suggest that policies should be directed at individual banks and not so much at the system as a whole. For example, we have seen that large banks' contributions to systemic risk matter most and this seems to suggest that regulation could focus on these banks in particular. For example, by having much higher capital requirements for the larger banks. Our research is just a first step in order to learn how to deal with financial bubbles at the microeconomic level. In a sense, our results are more illustrative because we haven't really clearly identified a causal relationship and this would be an important step to improve the identification of causal effects. And then of course we would like to analyze the potential policy implications in more detail so which role could monitor a policy play in dealing with financial bubbles, which role should financial regulation play, especially macro-credential regulation. But this of course then requires a different setup which looks more specifically at policy measures and tries to identify the causal effect.