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SCHEDULE IV REINSURANCE | 12 Months Ended
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Dec. 31, 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract] |
Schedule IV - Reinsurance | WHITE MOUNTAINS INSURANCE GROUP, LTD. REINSURANCE
Column A |  | Column B |  | Column C |  | Column D |  | Column E |  | Column F
$ in Millions Premiums Earned |  | Gross Amount |  | Ceded to Other Companies |  | Assumed from Other Companies |  | Net Amount |  | Percentage of Amount Assumed to Net
Year ended: |  |  |  |  |  |  |  |  |  |
December 31, 2021 |  |  |  |  |  |  |  |  |  |
HG Global/BAM |  | $ | 23.2 |  |  | $ | — |  |  | $ | 3.7 |  |  | $ | 26.9 |  |  | 13.8 | %
Ark |  | 886.4 |  |  | (249.1) |  |  | — |  |  | 637.3 |  |  | — |
December 31, 2020 |  |  |  |  |  |  |  |  |  |
HG Global/BAM |  | 19.4 |  |  | — |  |  | 3.4 |  |  | 22.8 |  |  | 14.9 |
December 31, 2019 |  |  |  |  |  |  |  |  |  |
HG Global/BAM |  | 13.6 |  |  | — |  |  | 2.7 |  |  | 16.3 |  |  | 16.6 |
Schedules of the Registrant should be read in conjunction with the Consolidated Financial Statements and Notes.

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- Definition The entire disclosure for the supplemental schedule of reinsurance information. Reinsurance schedule includes, but is not limited to, the type of insurance, gross amount of premiums, premiums ceded to other entities, premiums assumed from other entities, net amount of premium revenue, and the percentage of the premiums assumed to net premium revenue. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17) -URI http://asc.fasb.org/extlink&oid=120401096&loc=d3e574992-122915 + Details
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