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Employee Share-Based Incentive Compensation Plans (Tables) - White Mountains | 6 Months Ended
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Jun. 30, 2019
Share-based compensation arrangement by share-based payment award |
Summary of performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan | The following table presents the performance share activity for the three and six months ended June 30, 2019 and 2018 for performance shares granted under the WTM Incentive Plan:
|  | Three Months Ended June 30, |  | Six Months Ended June 30,
|  | 2019 |  | 2018 |  | 2019 |  | 2018
Millions, except share amounts |  | Target Performance Shares Outstanding |  | Accrued Expense |  | Target Performance Shares Outstanding |  | Accrued Expense |  | Target Performance Shares Outstanding |  | Accrued Expense |  | Target Performance Shares Outstanding |  | Accrued Expense
Beginning of period |  | 40,602 |  |  | $ | 23.1 |  |  | 40,616 |  |  | $ | 21.0 |  |  | 40,616 |  |  | $ | 31.7 |  |  | 50,515 |  |  | $ | 45.8 |
Shares paid (1) |  | — |  |  | — |  |  | — |  |  | — |  |  | (13,715 | ) |  | (18.1 | ) |  | (23,186 | ) |  | (28.4 | )
New grants |  | 1,900 |  |  | — |  |  | — |  |  | — |  |  | 15,600 |  |  | — |  |  | 14,105 |  |  | — |
Forfeitures and cancellations(2) |  | (29 | ) |  | (.2 | ) |  | — |  |  | (.1 | ) |  | (28 | ) |  | — |  |  | (818 | ) |  | .2 |
Expense recognized |  | — |  |  | 7.9 |  |  | — |  |  | 6.3 |  |  | — |  |  | 17.2 |  |  | — |  |  | 9.6 |
End of period |  | 42,473 |  |  | $ | 30.8 |  |  | 40,616 |  |  | $ | 27.2 |  |  | 42,473 |  |  | $ | 30.8 |  |  | 40,616 |  |  | $ | 27.2 |
(1) WTM performance share payments in 2019 for the 2016-2018 performance cycle, which were paid in cash in March 2019, ranged from 139% to 166% of target. WTM performance share payments in 2018 for the 2015-2017 performance cycle, which were paid in cash in March 2018, ranged from 145% to 147% of target. (2) Amounts include changes in assumed forfeitures, as required under GAAP.
Share-based Compensation, Performance Shares Award Outstanding Activity | The following table presents performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan as of June 30, 2019 for each performance cycle:
|  | Six Months Ended June 30, 2019
Millions, except share amounts |  | Target Performance Shares Outstanding |  | Accrued Expense
Performance cycle: |  |  |  |  |  |
2017 – 2019 |  | 14,070 |  |  | $ | 21.6 |
2018 – 2020 |  | 13,450 |  |  | 7.3 |
2019 – 2021 |  | 15,600 |  |  | 2.4 |
Sub-total |  | 43,120 |  |  | 31.3 |
Assumed forfeitures |  | (647 | ) |  | (.5 | )
June 30, 2019 |  | 42,473 |  |  | $ | 30.8 |
Summary of restricted shares activity | The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards for the three and six months ended June 30, 2019 and 2018:
|  | Three Months Ended June 30, |  | Six Months Ended June 30,
|  | 2019 |  | 2018 |  | 2019 |  | 2018
Millions, except share amounts |  | Restricted Shares |  | Unamortized Issue Date Fair Value |  | Restricted Shares |  | Unamortized Issue Date Fair Value |  | Restricted Shares |  | Unamortized Issue Date Fair Value |  | Restricted Shares |  | Unamortized Issue Date Fair Value
Non-vested, |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning of period |  | 41,495 |  |  | $ | 22.8 |  |  | 41,510 |  |  | $ | 22.2 |  |  | 41,510 |  |  | $ | 12.5 |  |  | 53,755 |  |  | $ | 14.3 |
Issued |  | 1,900 |  |  | 1.7 |  |  | — |  |  | — |  |  | 15,600 |  |  | 14.5 |  |  | 14,105 |  |  | 11.4 |
Vested |  | — |  |  | — |  |  | — |  |  | — |  |  | (13,715 | ) |  | — |  |  | (25,381 | ) |  | — |
Forfeited |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | (969 | ) |  | (.2 | )
Expense recognized |  | — |  |  | (2.6 | ) |  | — |  |  | (3.2 | ) |  | — |  |  | (5.1 | ) |  | — |  |  | (6.5 | )
End of period |  | 43,395 |  |  | $ | 21.9 |  |  | 41,510 |  |  | $ | 19.0 |  |  | 43,395 |  |  | $ | 21.9 |  |  | 41,510 |  |  | $ | 19.0 |

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