Changes in accounting policies, comparability and adjustments	6 Months Ended
	Jun. 30, 2021
Changes In Accounting Policies Comparability And Adjustments [Line Items]
Changes in accounting policies, comparability and adjustments	Amendments to IFRS 9, IAS 39 and IFRS 7 (Interest Rate Benchmark Reform – Phase 2) On 1 January 2021, UBS adopted Interest Rate Benchmark Reform – Phase 2, Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16 , addressing a number of issues in financial reporting areas that arise when interbank offered rates ( IBOR s) are reformed or replaced. The amendments provide a practical expedient which permits certain changes in the contractual cash flows of debt instruments attributable to the repl acement of IBOR s with alternative reference rates (ARRs) to be accounted for prospectively by updating the instrument’s effective interest rate (EIR) , provided ( i ) the change is necessary as a direct consequence of IBOR reform and (ii) the new basis for determining the contractual cash flows is economically equivalent to the previous basis. UBS adopted the amendments, which provide a practical expedient with no material effect on the Group’s financial statements. Furthermore, the amendments provide various hedge accounting reliefs, with the following expected to benefit UBS. – Risk components The amendments permit UBS to designate an alternative benchmark rate as a non-contractually specified risk component, even if it is not separately identifiable at the date when it is designated, provided UBS can reasonably expect that it will meet the requirements within 24 months of the first designation and the risk component is reliably measurable. As of 30 June 2021, the alternative benchmark rates that UBS has designated as the hedged risk in fair value hedges of interest rate risk related to debt instruments and cash flow hedges of forecast transactions were the Secured Overnight Financing Rate ( SOFR ) , the Swiss Average Rate Overnight (SARON) and the Sterling Overnight Index Average ( SONIA). The designated notionals were USD 11 b illio n , USD 1.1 billion and USD 0.7 billion, respectively. – Hedge designation Following amendments to the hedge documentation to reflect the change in designation relating to IBOR reform, UBS will continue its hedge relationships provided the other hedge accounting criteria and requirements of the p hase 2 amendment are met. As of 30 June 2021, no such changes have been made. – Amounts accumulated in the cash flow hedge reserve Upon changing the hedge designation as set out above, the accumulated amounts in the cash flow hedge reserve are assumed to be based on the alternative benchmark rate. For discontinued hedging relationships, when the interest rate benchmark on which the hedged future cash flows were based is changed as required by IBOR reform, the amount accumulated in the cash flow hedge reserve is also assumed to be based on the alternative benchmark rate for the purpose of assessing whether the hedged future cash flows are still expected to occur. As of 3 0 June 2021, no such changes have been made. – Retrospective effectiveness assessment as applied to hedges designated under IAS 39 U pon the end of the p hase 1 relief for effectiveness assessment UBS may elect to reset to zero the cumulative fair value changes of the hedged item and hedging instrument for the purpose of assessing the retrospective effectiveness of a hedging relationship. As of 30 June 2021, no such election has been made. › Refer to “Note 25 Hedge accounting” in the “Consolidated financial statements” section of the Annual Report 2020 for details about phase 1 accounting reliefs The amendments also introduced additional disclosure requirements regarding the Group’s management of the transition to alternative benchmark rates, its progress at the reporting date and the risks to which it is exposed arising from financial instruments because of the transition.