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EQUITY - Common and preferred shares outstanding (Details) - BRL (R$) R$ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Capital |  |  |
Shares exercise period when not a public offering | 30 days |  |
Shares exercise period for public offering | 10 days |  |
Total capital | R$ 19,249,181 | R$ 19,249,181 |
Reconciliations of common and preferred outstanding shares |  |  |
Number of shares outstanding at end of period | 1,698,941,000 |  |
Common shares |  |  |
Capital |  |  |
Authorized capital | 1,500,000,000 |  |
Shares subscribed and paid up | 573,627,483 |  |
Reconciliations of common and preferred outstanding shares |  |  |
Number of shares outstanding at beginning of the year | 571,929,945 | 571,929,945 | 571,929,945
Number of shares outstanding at end of period | 571,929,945 | 571,929,945 | 571,929,945
Preferred shares |  |  |
Capital |  |  |
Authorized capital | 3,000,000,000 |  |
Shares subscribed and paid up | 1,146,031,245 |  |
Reconciliations of common and preferred outstanding shares |  |  |
Number of shares outstanding at beginning of the year | 1,124,233,755 | 1,137,327,184 | 1,137,018,570
Acquisition of Treasury shares |  | (16,000,000) |
Exercise of stock options | 2,777,072 | 1,597,235 | 308,614
Transfer of shares |  | 1,309,336 |
Number of shares outstanding at end of period | 1,127,010,827 | 1,124,233,755 | 1,137,327,184

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