We propose an approach for assessing extreme impacts in a way that is simple and transparent. The proposal is based on undertaking a key impact deep dive (KIDD). This paper focuses on the application of a KIDD to assessing extreme operational risk losses in the banking sector and within the context of assessing operational risk capital. However, a KIDD has broader applications. For instance, it can be used as part of a stress test in any type of institution. Further, a KIDD can be generalized and applied to other risks (eg, credit and market risk) and other impact types such as brand damage, length of time without access to critical systems, loss of customers, staff morale, etc. A KIDD assessment has advantages over some established approaches for assessing extreme risks. For example, applying a KIDD approach can lead to increased business engagement and can reduce the number of full-time equivalent hours required to assess operational risk capital, since, unlike some of the established approaches used, such as in the banking sector, a KIDD does not require the use of sophisticated models. Further, a KIDD only requires a business to focus on analyzing a small number of impact types that are considered the most harmful to the business, instead of needing to quantify a potentially large set of risks or scenarios, as is often the practice. In the context of operational risk, the KIDD approach is predicated on the premise that extreme operational risk losses tend to be driven by a single large event and that operational risk losses are driven by only a small number of loss types.