Ever since the global financial crisis (GFC), economies worldwide have been trying to recover from the worldwide recession. Central Banks have thus introduced different un-conventional monetary policies to ensure additional monetary stimulus: however, with inflation still not meeting the wanted target and banks hoarding reserves, Central Banks introduced yet another radical monetary policy; Negative Interest Rate Policy (NIRP). The purpose of this research was to assess whether there have been changes in the way banks operate and make money during the period of negative interest rate. The theoretical framework of this thesis was comprised of literature on negative interest rates as well as literature on the various tools of monetary policies. The research questions were the following: Has the ratio of banks’ net interest to total revenue changed in the period of 2010-2020? Did banks cut expenses to make up for possible loss in profit? Have banks increased fees to battle possible loss of income? Has the most important source of income changed due to NIRP? With both qualitative and quantitative data this research strived to answer the research questions using mixed method, where quantitative data sought to be explained by qualitative data. This research concludes that banks changed operating ways, but only slightly as the decrease of profit and net interest rate ratio made banks compensate for lost income with various fees and commissions. Negative interest motivated banks to develop new products, services and focus more on gains from non-interest in-come.