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EQUITY - Ownership of shares (Details) - BRL (R$) R$ in Thousands | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
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EQUITY |  |  |
Shares subscribed and paid up | 1,719,658,728 | 1,719,658,728 | 1,719,658,728
Ownership of shares, as a percentage of total issued shares | 100.00% | 100.00% | 100.00%
Total capital | R$ 19,249,181 | R$ 19,249,181 |
Common shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 573,627,483 | 573,627,483 | 573,627,483
Ownership of shares, as a percentage of total issued shares | 100.00% | 100.00% | 100.00%
Preferred shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 1,146,031,245 | 1,146,031,245 | 1,146,031,245
Ownership of shares, as a percentage of total issued shares | 100.00% | 100.00% | 100.00%
Treasury Stocks |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 18,497,296 | 20,717,956 | 23,495,028
Ownership of shares, as a percentage of total issued shares | 1.10% | 1.20% | 1.40%
Treasury Stocks | Common shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 1,697,538 | 1,697,538 | 1,697,538
Ownership of shares, as a percentage of total issued shares | 0.30% | 0.30% | 0.30%
Treasury Stocks | Preferred shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 16,799,758 | 19,020,418 | 21,797,490
Ownership of shares, as a percentage of total issued shares | 1.50% | 1.70% | 1.90%
Metalurgica Gerdau S.A. |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 560,046,701 | 627,751,085 | 653,368,823
Ownership of shares, as a percentage of total issued shares | 32.60% | 36.50% | 38.00%
Metalurgica Gerdau S.A. | Common shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 557,898,901 | 557,898,901 | 557,898,901
Ownership of shares, as a percentage of total issued shares | 97.30% | 97.30% | 97.30%
Metalurgica Gerdau S.A. | Preferred shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 2,147,800 | 69,852,184 | 95,469,922
Ownership of shares, as a percentage of total issued shares | 0.20% | 6.10% | 8.30%
Brazilian institutional investors |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 230,660,486 | 244,766,757 | 226,456,754
Ownership of shares, as a percentage of total issued shares | 13.40% | 14.20% | 13.20%
Brazilian institutional investors | Common shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 3,397,955 | 3,068,614 | 2,383,207
Ownership of shares, as a percentage of total issued shares | 0.60% | 0.50% | 0.40%
Brazilian institutional investors | Preferred shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 227,262,531 | 241,698,143 | 224,073,547
Ownership of shares, as a percentage of total issued shares | 19.80% | 21.10% | 19.60%
Foreign institutional investors |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 495,218,544 | 431,611,203 | 415,223,778
Ownership of shares, as a percentage of total issued shares | 28.80% | 25.10% | 24.10%
Foreign institutional investors | Common shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 3,142,148 | 3,875,655 | 4,836,488
Ownership of shares, as a percentage of total issued shares | 0.50% | 0.70% | 0.80%
Foreign institutional investors | Preferred shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 492,076,396 | 427,735,548 | 410,387,290
Ownership of shares, as a percentage of total issued shares | 42.90% | 37.30% | 35.80%
Other shareholders |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 415,235,701 | 394,811,727 | 401,114,345
Ownership of shares, as a percentage of total issued shares | 24.10% | 23.00% | 23.30%
Other shareholders | Common shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 7,490,941 | 7,086,775 | 6,811,349
Ownership of shares, as a percentage of total issued shares | 1.30% | 1.20% | 1.20%
Other shareholders | Preferred shares |  |  |
EQUITY |  |  |
Shares subscribed and paid up | 407,744,760 | 387,724,952 | 394,302,996
Ownership of shares, as a percentage of total issued shares | 35.60% | 33.80% | 34.40%

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