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CONDENSED CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDER'S EQUITY (UNAUDITED) - USD ($) $ in Millions | Total | Common Stock Outstanding | Paid-in Capital | Retained Earnings | AOCI | Total Equity Attributable to Spire Shareholders | Noncontrolling Interest | Spire Missouri | Spire Missouri Common Stock Outstanding | Spire Missouri Paid-in Capital | Spire Missouri Retained Earnings | Spire Missouri AOCI | Spire Alabama | Spire Alabama Common Stock Outstanding | Spire Alabama Paid-in Capital | Spire Alabama Retained Earnings
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Beginning Balance, (in shares) at Sep. 30, 2016 |  | 45,650,642 |  |  |  |  |  |  | 24,577 |  |  |  |  | 1,972,052 |  |
Beginning Balance at Sep. 30, 2016 | $ 1,768.2 | $ 45.6 | $ 1,175.9 | $ 550.9 | $ (4.2) | $ 1,768.2 | $ 0.0 |  |  |  |  |  |  |  |  |
Beginning Balance at Sep. 30, 2016 |  |  |  |  |  |  |  | $ 1,068.5 | $ 0.1 | $ 751.9 | $ 318.3 | $ (1.8) | $ 867.3 | $ 0.0 | $ 451.9 | $ 415.4
Stockholders' Equity Rollforward |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income | 45.2 |  |  | 45.2 |  | 45.2 |  | 38.0 |  |  | 38.0 |  | 10.3 |  |  | 10.3
Dividend reinvestment plan (in shares) |  | 5,610 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend reinvestment plan | 0.3 |  | 0.3 |  |  | 0.3 |  |  |  |  |  |  |  |  |  |
Stock-based compensation costs | 1.7 |  | 1.7 |  |  | 1.7 |  | 1.1 |  | 1.1 |  |  |  |  |  |
Stock issued under stock-based compensation plans (in shares) |  | 110,136 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock issued under stock-based compensation plans | 0.0 | $ 0.1 | (0.1) |  |  | 0.0 |  |  |  |  |  |  |  |  |  |
Employee's tax withholding for stock-based compensation (in shares) |  | (33,615) |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee’s tax withholding for stock-based compensation | (2.1) |  | (2.1) |  |  | (2.1) |  |  |  |  |  |  |  |  |  |
Dividends declared | (24.0) |  |  | (24.0) |  | (24.0) |  | (14.7) |  |  | (14.7) |  | (6.7) |  |  | (6.7)
Other comprehensive income (loss), net of tax | 7.4 |  |  |  | 7.4 | 7.4 |  | 0.2 |  |  |  | 0.2 |  |  |  |
Ending Balance, (in shares) at Dec. 31, 2016 |  | 45,732,773 |  |  |  |  |  |  | 24,577 |  |  |  |  | 1,972,052 |  |
Ending Balance at Dec. 31, 2016 | 1,796.7 | $ 45.7 | 1,175.7 | 572.1 | 3.2 | 1,796.7 | 0.0 |  |  |  |  |  |  |  |  |
Ending Balance at Dec. 31, 2016 | 1,796.7 |  |  |  |  |  |  | 1,093.1 | $ 0.1 | 753.0 | 341.6 | (1.6) | 870.9 | $ 0.0 | 451.9 | 419.0
Beginning Balance, (in shares) at Sep. 30, 2017 |  | 48,263,243 |  |  |  |  |  |  | 24,577 |  |  |  |  | 1,972,052 |  |
Beginning Balance at Sep. 30, 2017 | 1,991.3 | $ 48.3 | 1,325.6 | 614.2 | 3.2 | 1,991.3 | 0.0 |  |  |  |  |  |  |  |  |
Beginning Balance at Sep. 30, 2017 | 1,991.3 |  |  |  |  |  |  | 1,171.0 | $ 0.1 | 756.1 | 416.5 | (1.7) | 867.4 | $ 0.0 | 420.9 | 446.5
Stockholders' Equity Rollforward |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income | 116.0 |  |  | 116.0 |  | 116.0 |  | 89.4 |  |  | 89.4 |  | (49.6) |  |  | (49.6)
Business combination | 6.5 |  |  |  |  |  | 6.5 |  |  |  |  |  |  |  |  |
Dividend reinvestment plan (in shares) |  | 4,618 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend reinvestment plan | 0.3 |  | 0.3 |  |  | 0.3 |  |  |  |  |  |  |  |  |  |
Stock-based compensation costs | 1.9 |  | 1.9 | 0.0 |  | 1.9 |  | 1.1 |  | 1.1 |  |  |  |  |  |
Stock issued under stock-based compensation plans (in shares) |  | 105,434 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock issued under stock-based compensation plans | 0.0 | $ 0.1 | (0.1) |  |  | 0.0 |  |  |  |  |  |  |  |  |  |
Employee's tax withholding for stock-based compensation (in shares) |  | (33,581) |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee’s tax withholding for stock-based compensation | (2.9) | $ (0.1) | (2.8) |  |  | (2.9) |  |  |  |  |  |  |  |  |  |
Dividends declared | (27.2) |  |  | (27.2) |  | (27.2) |  | (13.5) |  |  | (13.5) |  | (7.5) |  |  | (7.5)
Other comprehensive income (loss), net of tax | (0.2) |  |  |  | (0.2) | (0.2) |  | 0.0 |  |  |  |  |  |  |  |
Ending Balance, (in shares) at Dec. 31, 2017 |  | 48,339,714 |  |  |  |  |  |  | 24,577 |  |  |  |  | 1,972,052 |  |
Ending Balance at Dec. 31, 2017 | 2,085.7 | $ 48.3 | $ 1,324.9 | $ 703.0 | $ 3.0 | $ 2,079.2 | $ 6.5 |  |  |  |  |  |  |  |  |
Ending Balance at Dec. 31, 2017 | $ 2,079.2 |  |  |  |  |  |  | $ 1,248.0 | $ 0.1 | $ 757.2 | $ 492.4 | $ (1.7) | $ 810.3 | $ 0.0 | $ 420.9 | $ 389.4

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