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Schedule II VALUATION AND QUALIFYING ACCOUNTS | 12 Months Ended
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Dec. 31, 2025
Schedule II VALUATION AND QUALIFYING ACCOUNTS |
Schedule II VALUATION AND QUALIFYING ACCOUNTS | Schedule II COGENT COMMUNICATIONS HOLDINGS, INC. AND SUBSIDIARIES VALUATION AND QUALIFYING ACCOUNTS (in thousands) ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Balance at | ​ | Charged to | ​ | ​ | ​ | ​ | Balance at
​ | ​ | Beginning of | ​ | Costs and | ​ | ​ | ​ | ​ | End of
Description | ​ ​ ​ | Period | ​ ​ ​ | Expenses | ​ ​ ​ | (Deductions) | ​ ​ ​ | Period
Deferred tax valuation allowance | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Year ended December 31, 2023 |  | $ | 140,895 | ​ | $ | 10,486 | ​ | $ | (14,848) | ​ | $ | 136,533
Year ended December 31, 2024 |  | $ | 136,533 | ​ | $ | 2,055 | ​ | $ | (6,815) | ​ | $ | 131,773
Year ended December 31, 2025 |  | $ | 131,773 | ​ | $ | 17,317 | ​ | $ | (1,035) | ​ | $ | 148,055
​

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- Definition The entire disclosure for valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 09 -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4 + Details
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- References No definition available. + Details
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