Note 1 Basis of Accounting

UBS AG's ("UBS") consolidated financial statements (Financial Statements) are prepared in accordance with International Financial Reporting Standards (IFRS) and stated in Swiss francs (CHF). These Financial Statements are presented in accordance with IAS 34 Interim Financial Reporting. In preparing the interim Financial Statements, the same accounting principles and methods of computation are applied as in the Financial Statements on 31 December 2006 and for the year then ended except for the changes set out below. The interim Financial Statements are unaudited. In the opinion of management, all adjustments necessary for a fair presenta­tion of the financial position, results of operations and cash flows for the interim periods have been made. These interim Financial Statements should be read in conjunction with the audited Financial Statements included in the UBS Financial Report 2006.

Changes in accounting policies and presentation

Application of IFRS 7 Financial Instruments: Disclosures

On 1 January 2007, UBS adopted the disclosure requirements for financial instruments under IFRS 7. The new standard has no impact on recognition, measurement and presentation of financial instruments. Accordingly, the first-time adoption of IFRS 7 has no effect on Net profit and Equity. Rather, it requires entities to provide disclosures in their financial statements that enable users to evaluate: a) the significance of financial instruments for the entity's financial position and performance, and b) the nature and extent of the credit, market and liquidity risks arising from financial instruments during the period and at the reporting date, and how the entity manages those risks. The disclosure principles of IFRS 7 complement the principles for recognizing, measuring and presenting financial assets and financial liabilities in IAS 32 Financial Instruments: Presentation and IAS 39 Financial Instruments: Recognition and Measurement. The new disclosure requirements will mainly impact UBS's 2007 Financial Statements rather than the quarterly Financial ­Statements.

UBS has entered into transactions for which fair value is determined using valuation models for which not all inputs are market-observable prices or rates. Such financial instruments are initially recognized in UBS's Financial Statements at the transaction price, which is generally the best indicator of fair value, although the value obtained from the relevant valuation model may differ. Where such differences arise, UBS is required by IFRS 7 to disclose: a) its accounting policy for recognizing that difference in profit or loss to reflect a change in factors (including time) that market participants would consider in setting a price, and b) the aggregate difference yet to be recognized in profit or loss at the beginning and end of the period and a reconciliation of changes in the balance of this difference (movement of deferred day 1 profit or loss). The respective accounting policy is reflected in Note 1 to the Financial Statements 2006. For the movement of the deferred day 1 profit or loss, refer to Note 9 of this report.

Net interest and trading income

Starting first quarter 2007, UBS provides a breakdown of total net interest and trading income by businesses (trading businesses, interest margin businesses, treasury activities and other) in Note 3.