10.	PREFERRED AND COMMON STOCKHOLDER’S EQUITY

The Company is authorized to issue up to 5.0 shares of preferred stock, par value $0.01 per share. There were no preferred shares outstanding at June 30, 2018, 2017 and 2016.

The Company is authorized to issue up to 150.0 shares of common stock, par value $0.01 per share. There were 70.6, 68.4, and 69.1 shares issued and outstanding at June 30, 2018, 2017 and 2016 respectively.

Common shares issued and outstanding

	Years Ended June 30,
		2018	2017		2016
Common stock issued and outstanding at July 1		68.4	69.1		68.9
Common stock issued upon exercise of options and employee stock plans		2.2	0.9		4.7
Repurchase and retirement of common stock		—	(1.6	)	(4.5	)
Common stock issued and outstanding at June 30		70.6	68.4		69.1

Stock Repurchase Program

In June 2016, the Company’s Board of Directors authorized an eighth share repurchase program of $200.0 of the Company’s outstanding common stock. The Company plans to repurchase its common stock from time to time or on an accelerated basis through open market transactions or privately negotiated transactions as determined by the Company’s management. The amount and timing of stock repurchases under the program will depend on business and market conditions, stock price, trading restrictions, acquisition activity and other factors. As of June 30, 2018, the Company has $160.7 remaining on its current share repurchase authorization.

The Company uses the par value method of accounting for its stock repurchases. As a result of the stock repurchases, the Company reduced common stock and additional paid-in capital and recorded charges to retained earnings/accumulated deficit. The shares retired, aggregate common stock and additional paid-in capital reductions, and related charges to retained earnings/accumulated deficit for the repurchases for periods ended June 30, 2018, 2017 and 2016 were as follows:

	Year ended June 30,
	2018		2017		2016
Shares purchased and retired		-		1.6		4.5
Common stock and additional paid-in-capital reductions	$	-	$	14.6	$	41.2
Charges to retained earnings	$	-	$	17.0	$	121.4