Non-qualified intermediaries (NQIs) are by far the most common type of financial institutions receiving US-sourced income. There are only about 5000 qualified intermediaries (QIs); every other financial institution is an NQI. NQIs are also deemed by the US to be facilitators of tax evasion, which means that they are more rigorous disclosure obligations and risk of higher penalties for non-compliance. This chapter explains the most common issues faced by NQIs and also by QIs with NQI clients.