Exhibit 99.1

Itaú Announcement to the Market Disclosure of results for the third quarter and from January to September of 2020, according to International Financial Reporting Standards – IFRS We present below the differences between our financial statements in BRGAAP and in International Financial Reporting Standards – IFRS. As from January 1st, 2018, IFRS 9 came into effect, the accounting standard that replaces IAS 39 in the treatment of Financial Instruments. The new standard is structured to encompass the pillars of classification, measurement of financial assets and impairment and was applied retrospectively by Itaú Unibanco Holding. The complete consolidated financial statements under IFRS from January to September 2020 are available at our website: www.itau.com.br/investor-relations. Comparison between BRGAAP1 and IFRS R$ million Adjustments and Adjustments and BRGAAP Reclassifications IFRS BRGAAP Reclassifications IFRS Balance Sheet 2 2 Sep/30/2020 Dec/31/2019 Total Assets 2,110,120 (111,836) 1,998,284 1,738,713 (101,232) 1,637,481 Cash, Compulsory Deposits and Financial Assets At Amortized Cost 3 4 6 1,452,126 (22,318) 1,429,808 1,164,753 3,535 1,168,288 (-) Provision for Expected Loss at Amortized Cost 5 (50,208) 3,506 (46,702) (38,888) 2,859 (36,029) Financial Assets at Fair Value Through Other Comprehensive Income 4 183,882 (90,073) 93,809 166,676 (89,930) 76,746 (-) Expected Loss at Fair Value Through Other Comprehensive Income 5 (3,445) 3,327 (118) (3,162) 3,076 (86) Financial Assets at Fair Value Through Profit or Loss 4 396,328 (4,011) 392,317 345,677 (22,748) 322,929 Tax Assets 7 79,345 (6,874) 72,471 56,835 (7,875) 48,960 Investments in Associates and Joint Ventures, Goodwill, Fixed Assets,Intangible Assets, Assets Held for Sale and Other Assets 52,092 4,607 56,699 46,822 9,851 56,673 Total Liabilities 1,967,754 (117,398) 1,850,356 1,595,865 (107,849) 1,488,016 Financial Assets at Amortized Cost 3 6 1,594,801 (113,812) 1,480,989 1,265,471 (105,641) 1,159,830 Financial Assets at Fair Value Through Profit or Loss 4 78,569 449 79,018 48,008 21 48,029 Provision for Expected Loss (Loan Commitments and Financial Guarantees) 5 1,030 3,651 4,681 959 3,181 4,140 Provision for Insurance and Pension Plan 215,085 1,253 216,338 217,216 1,118 218,334 Provisions 19,789 (1) 19,788 21,454 - 21,454 Tax Liabilities 7 10,894 (4,251) 6,643 13,870 (5,979) 7,891 Other Liabilities 47,586 (4,687) 42,899 28,887 (549) 28,338 Total Stockholders’ Equity 142,367 5,562 147,928 142,848 6,617 149,465 Non-controlling Interests 11,808 295 12,103 10,861 1,679 12,540 Total Controlling Stockholders’ Equity 8 130,559 5,267 135,825 131,987 4,938 136,925 1 BRGAAP represents accounting practices in force in Brazil for financial institutions, according to regulation of the Central Bank of Brazil; 2 Resulted from reclassification of assets and liabilities and other effects from the adoption of IFRS; 3 Resulted from the elimination of transactions between parent company and exclusive funds (particularly PGBL and VGBL funds), which are consolidated under IFRS; 4 Refer to reclassification of financial assets between measurement categories at fair value and amortized cost; 5 Application of criterion for calculation of Expected Loss as set forth by IFRS; 6 Difference in accounting, particularly from Foreign Exchange Portfolio, which are now be presented as net effect between Assets and Liabilities; 7 Difference in accounting, particularly deffered taxes, which are now accounted for as net effect between Assets and Liabilities in each one of the consolidated companies; 8 Reconciliation of Controlling Stockholders’ Equity is presented in the following table. Itaú Unibanco Holding S.A.

Below is the reconciliation of Results to Stockholders’ Equity, with the conceptual description of major adjustments. R$ million Stockholders Result * Reconciliation Equity * Sep/30/2020 3rd Q/20 2nd Q/20 3rd Q/19 jan-sep/20 jan-sep/19 BRGAAP - Values Attributable to Controlling Stockholders 130,559 4,492 3,424 5,576 11,317 19,101 (a) Expected Loss - Loan and Lease Operations and Other Financial Assets 1,854 25 249 (240) 138 (391) (b) Adjustment to Fair Value of Financial Assets (1,059) (8) (257) (108) (391) 11 (c) Acquisition of Interest in Porto Seguro Itaú Unibanco Participações S.A. 436 (1) (1) (1) (3) (3) (d) Criteria for Write-Off of Financial Assets 1,922 (49) 65 (190) (5) (253) (e) Financial Lease Operations 99 (25) (32) (30) (94) (111) (f) Other adjustments 2,015 298 (1,725) 158 (1,048) 85 IFRS - Values Attributable to Controlling Stockholders 135,825 4,732 1,723 5,165 9,914 18,439 IFRS - Values Attributable to Minority Stockholders 12,103 367 (3,626) 340 (3,040) 659 IFRS - Values Attributable to Controlling Stockholders and Minority Stockholders 147,928 5,099 (1,903) 5,505 6,874 19,098 * Events net of tax effects Differences between IFRS and BRGAAP Financial Statements (a) In the adoption of IFRS 9, there was a change in the calculation model of incurred loss (IAS 39) to expected loss, considering forward-looking information. On BRGAAP, the concept of Expected Loss is used, pursuant to BACEN Resolution No. 2,682/99.9 (b) Under IFRS, stocks and quotas classified as permanent investments were measured at fair value and its gains and losses were recorded directly in Result. Additionally, there was a change in the model of classification and measurement of financial assets due to the new categories introduced by IFRS 9. (c) Under IFRS, the effect of accounting at fair value of the acquisition of interest in Porto Seguro Itaú Unibanco Participações S.A. was recognized. (d) Criterion for write-off of financial assets on IFRS considers the recovery expectative. (e) Under IFRS (IAS 17) the financial lease operations are recorded as Fixed Assets, as a contra-entry of Other Financial Liabilities. Under BRGAAP, as from September 30th, 2015, the consideration of these transactions are now recorded in result, in accordance with CMN Resolution No. 3,617/08. (f) Other Adjustments is mainly due to the impairment of goodwill and intangible assets of Itaú Corpbanca in the 2nd Q/20 and reversal of the Amortization of Goodwill under BRGAAP. 9 More details in the Complete Financial Statements for January to September, 2020. For comparison purposes, we present on the table below the Result and Recurring Result in IFRS and BRGAAP. R$ million Recurring Result 3rd Q/20 3rd Q/19 BRGAAP IFRS Variation BRGAAP IFRS Variation Result - Attributable to Controlling Stockholders 4,492 4,732 240 5,576 5,165 (411) Exclusion of the Non-Recurring Events (539) (363) 176 (1,580) (1,431) 149 Mark to market of collateralized securities (346) (346) - - - - Goodwill amortization (169) - 169 (149) - 149 Voluntary severance program - - - (1,431) (1,431) - Other (24) (17) 7 - - - Recurring Result - Attributable to Controlling Stockholders 5,030 5,095 65 7,156 6,596 (560) The tables in this report show the figures in million. Variations and summations, however, were calculated in units. São Paulo, November 3rd, 2020 Alexsandro Broedel Group Executive Finance Director and Head of Investor Relations Itaú Unibanco Holding S.A.