Exhibit 99.1

Announcement to the Market

Disclosure of results for the third quarter and from January to September of 2017,
according to International Financial Reporting Standards – IFRS

We present below the differences between our financial statements in BRGAAP¹ and in International Financial Reporting Standards - IFRS. We emphasize that the main difference in the result and equity relates to the allowance for loan losses, that uses the concept of incurred loss in IFRS and of expected loss in BRGAAP.

The complete consolidated financial statements under IFRS for January to September 2017 are available at our website: www.itau.com.br/investor-relations

Comparison between BRGAAP¹ and IFRS

													R$ million
Balance Sheet	BRGAAP			Adjustments and Reclassifications2			IFRS			BRGAAP			Adjustments and Reclassifications2			IFRS
				Sep/30/2017									Dec/31/2016
Total Assets		1,466,000			(92,482	)		1,373,518			1,427,084			(73,843	)		1,353,241
Cash and Cash Equivalents, Reserve Requirements, Interbank Deposits, Securities Under Repurchase Agreements, Financial Assets and Derivatives 3		814,453			(16,528	)		797,926			767,222			(16,395	)		750,827
Loan Operations		467,831			218			468,049			491,225			(859	)		490,366
(-) Allowance for Loan Losses 4		(34,702	)		7,340			(27,362	)		(35,986	)		9,014			(26,972	)
Other Financial Assets 5		119,494			(63,317	)		56,177			106,458			(52,541	)		53,917
Tax Assets 6		59,954			(20,732	)		39,221			61,210			(16,936	)		44,274
Investments in associates and jointly controlled entities, Goodwill, Fixed and Intangible Assets, Assets Held for Sale and Other Assets		38,970			537			39,507			36,954			3,875			40,829
Current Liabilities and Long Term Liabilities		1,330,861			(101,034	)		1,229,827			1,299,869			(81,442	)		1,218,427
Deposits		359,904			-			359,904			329,414			-			329,414
Deposits Received Under Securities Repurchase Agreements 3		336,951			(17,758	)		319,193			366,038			(16,874	)		349,164
Financial Liabilities Held for Trading, Derivatives, Interbank and Institutional funding		248,051			5			248,055			257,167			(228	)		256,939
Other Financial Liabilities 5		130,167			(62,664	)		67,503			123,604			(51,772	)		71,832
Reserves for Insurance, Private Pension and Capitalization		177,521			331			177,852			156,656			567			157,223
Provisions and Other Liabilities		56,559			(5,795	)		50,764			49,320			(1,301	)		48,019
Tax Liabilities 6		21,708			(15,153	)		6,556			17,670			(11,834	)		5,836
Total Stockholders' Equity		135,139			8,552			143,691			127,215			7,599			134,814
Non-controlling interests		11,508			773			12,281			11,625			607			12,232
Controlling Stockholders' Equity 7		123,631			7,779			131,410			115,590			6,992			122,582

¹ BRGAAP represents the accounting practices adopted in Brazil for financial institutions, according to regulation of the Brazilian Central Bank;

² Resulted from reclassifications between assets and liabilities and other effects from IFRS adoption;

³ Resulted from the elimination of transactions between the parent company and exclusive funds (mainly PGBL and VGBL fund quotas), which are consolidated under IFRS;

⁴ Implementation of the criteria for calculating the Allowance for Loan Losses as defined in IFRS;

⁵ Difference in accounting, mainly for Foreign Exchange Portfolio, which started to be considered as net effect of Assets and Liabilities;

⁶ Difference in accounting, mainly for deferred taxes, which are now treated as a net effect of Assets and Liabilities in each of the consolidated companies;

⁷ Conciliation of Controlling Stockholders’ Equity is presented in the following table.

Itaú Unibanco Holding S.A.

 

Below, the conciliation of the Result and Equity, and the conceptual description of the major adjustments.

Conciliation

																R$ million
Adjustments	Equity			Result
	Sep/30/2017			3rdQ/17			2ndQ/17			3rdQ/16			jan-sep/17			jan-sep/16
BRGAAP - Values Attributable to Controlling Stockholders		123,631			6,077			6,014			5,394			18,143			16,097
(a) Allowance for Loan Losses		5,548			(89	)		71			24			(166	)		1,085
(b) Adjustment to market value of shares and quotas		305			-			-			-			-			-
(c) Acquisition of interest in Porto Seguro Itaú Unibanco Participações S.A.		453			(4	)		(3	)		(4	)		(11	)		(11	)
(d) Effective interest rate		(77	)		(2	)		1			5			(1	)		25
(e) Financial Leasing Operation		626			(33	)		(34	)		37			(91	)		123
(f) Other adjustments		924			98			320			105			544			(47	)
IFRS - Values Attributable to Controlling Stockholders		131,410			6,048			6,369			5,561			18,418			17,271
IFRS - Values Attributable to Minority Stockholders		12,281			(130	)		423			61			170			371
IFRS - Values Attributable to Controlling Stockholders and Minority Stockholders		143,691			5,918			6,792			5,622			18,588			17,642
Differences between IFRS and BRGAAP Financial Statements

(a) On IFRS (IAS 39), loan losses allowances must be made when there is objective evidence that loan operations have suffered a reduction In Its value (Incurred Loss). On BRGAAP, the expected less model Is used ⁸.

(b) On IFRS (IAS 39 and 32), stocks and quotas classified as permanent investments were measured at fair value and its gains and losses were recorded directly on Equity, with no Impact on the Income statement of the period.

(c) On IFRS, the effect of accounting at fair value the acquisition of the participation in Porto Seguro Itaú Unibanco Participações S.A. was recognized.

(d) On the IFRS (IAS 39), the assets and financial liabilities measured at amortized cost are recognized according to the methodology of effective Interest rate, which appropriates the revenues and costs directly attributed to the acquisition. Issue or disposal for the period of operation. On BRGAAP, the recognition of expenses and revenues from fees occurs at the time of contracting these operations.

(e) Under IFRS (IAS 17) the financial leasing operations are recorded as Fixed Assets on the other hand of Other Financial Liabilities. On BRGAAP, as of September 30, 2015, the consideration of these transactions are now recorded in income in accordance with CMN Resolution No. 3,617/08.

(f) Other Adjustments mainly comprise the difference in the eligibility of operations of the Cash Flow Hedge for purposes of IFRS and the reversal of the Goodwill Amortizations pursuant the BRGAAP.

⁸ For more details see our Complete Financial Statements for Jaunuary to September, 2017

For comparison purposes, we present on the table below the Result and the Recurring Result according to the IFRS and the BRGAAP.

																												R$ million
Recurring Result	3rdQ/17									2ndQ/17									jan-sep/17									jan-sep/16
	BRGAAP			IFRS			Variation			BRGAAP			IFRS			Variation			BRGAAP			IFRS			Variation			BRGAAP			IFRS			Variation
Result - Attributale to Controlling Stockholders		6,077			6,048			(29	)		6,014			6,369			355			18,143			18,418			275			16,097			17,271			1,174
Exclusion of the Non-Recurring Events		177			52			(125	)		155			31			(123	)		455			72			(383	)		308			140			(168	)
Goodwill Amortization		125			-			(125	)		123			-			(123	)		373			-			(373	)		308			-			(308	)
Disposal of IRB shares		(155	)		(155	)		-			-			-			-			(155	)		(155	)		-			-			-			-
Provision for Contingencies		70			70			-			55			55			-			143			143			-			143			143			-
Civil Lawsuits - Economic Plans		61			61			-			22			22			-			101			101			-			136			136			-
Tax and Social Security		9			9			-			33			33			-			42			42			-			6			6			-
Impairment		137			137			-			7			7			-			144			144			-			9			9			-
Program for the Settlement or Installment Payment of Taxes		-			-			-			-			-			-			-			-			-			(12	)		(12	)		-
Others		-			-			-			(31	)		(31	)		-			(51	)		(60	)		(10	)		(140	)		-			140
Recurring Result - Attributable to Controlling Stockholders		6,254			6,100			(154	)		6,169			6,400			231			18,599			18,490			(109	)		16,405			17,410			1,006

The tables in this report show the figures in millions. Variations and summations, however, are calculated in units.

São Paulo, October 30, 2017.

Alexsandro Broedel Lopes

Investor Relations Officer

Itaú Unibanco Holding S.A.