The Company is authorized to issue an unlimited number of Common Shares, an unlimited number of First Preferred Shares and an unlimited number of Second Preferred Shares. At December 31, 2018, no First or Second Preferred Shares had been issued.

The following table summarizes information related to Common Share balances as at December 31:



(number of shares in millions)	2018		2017		2016
Share capital, January 1	144.9		146.3		153.0
CP Common Shares repurchased	(4.6	)	(1.9	)	(6.9	)
Shares issued under stock option plan	0.2		0.5		0.2
Share capital, December 31	140.5		144.9		146.3

The change in the “Share capital” balance includes $12 million of stock-based compensation transferred from “Additional paid-in capital” (2017 – $12 million; 2016 – $5 million).

On April 20, 2016, the Company announced the renewal of its normal course issuer bid ("NCIB"), commencing May 2, 2016 to May 1, 2017, to purchase up to 6.91 million of its outstanding Common Shares for cancellation. The Company completed this NCIB on September 28, 2016.

On May 10, 2017, the Company announced a new NCIB, commencing May 15, 2017, to purchase up to 4.38 million Common Shares for cancellation before May 14, 2018. The Company completed this NCIB on May 10, 2018.

On October 19, 2018, the Company announced a new NCIB, commencing October 24, 2018, to purchase up to 5.68 million Common Shares for cancellation before October 23, 2019. As at December 31, 2018, the Company had purchased 2.19 million Common Shares for $568 million under this NCIB program.

All purchases are made in accordance with the respective NCIB at prevalent market prices plus brokerage fees, or such other prices that may be permitted by the Toronto Stock Exchange, with consideration allocated to share capital up to the average carrying amount of the shares, and any excess allocated to "Retained earnings".

The following table provides the activities under the share repurchase programs:



	2018		2017		2016
Number of Common Shares repurchased⁽¹⁾	4,683,162		1,888,100		6,910,000
Weighted-average price per share⁽²⁾	$	240.68	$	201.53	$	175.08
Amount of repurchase (in millions)⁽²⁾	$	1,127	$	381	$	1,210

⁽¹⁾Includes shares repurchased but not yet cancelled at year end.