The Product Owner confirms the achievement of organizational benefits throughout the project, as well as upon completion of the User Stories in the Prioritized Product Backlog. Benefits from Scrum projects are realized during Demonstrate and Validate Sprint, Retrospect Sprint, Ship Deliverables and Retrospect Project processes.
Reference: http://www.cs.vsu.ru/~svv/spm/SBOK_Guide_3rd_edition_English_Sample.pdf

Because stakeholders have an interest in the project, it is important to communicate with them regarding risks. Information provided to stakeholders related to risk should include potential impact and the plans for responding to each risk. This communication is on-going and should occur in parallel with the four sequential steps discussed thus far-risk identification, assessment, prioritization and mitigation. The Scrum Team may also discuss specific risks related to their Tasks with the Scrum Master during Daily Standup Meetings. The Product Owner is responsible for the prioritization of risks and for communicating the prioritized list to the Scrum Team. An important tool which can be used for communicating information related to risks is the Risk Burndown Chart.
Reference: http://blog.scrumstudy.com/risk-management-in-scrum/