STOCK OPTIONS (Tables)

12 Months Ended

May 31, 2013

STOCK OPTIONS [Abstract]

Option activity

Greystone has a stock option plan that provides for the granting of options to key employees and non-employee directors. The options are to purchase common stock at not less than fair market value at the date of the grant.  Effective May 5, 2012, Greystone's board of directors approved the renewal and extension of Greystone's stock option plan through May 11, 2021 and increased the maximum number of shares of common stock for which options may be granted to 2,500,000 of which 25,000 were available for grant at May 31, 2013.  Stock options generally expire in ten years from date of grant or upon termination of employment and are generally exercisable one year from date of grant in cumulative annual installments of 25%. Following is a summary of option activity for the two years ended May 31, 2013:

	Number	Weighted Average Exercise Price	Remaining Contractual Life (years)	Intrinsic Value
Total outstanding, May 31, 2012	1,400,000	$0.53
Awarded during fiscal 2013	2,100,000	$0.12
Expired during fiscal year 2013	(1,050,000)	$0.61
Total outstanding May 31, 2013	2,450,000	$0.16	7.8
Exercisable as of May 31, 2013	875,000	$0.23	5.7	$ 99,750
Non-vested as of May 31, 2013	1,575,000	$0.12	9.0	$299,250

Assumptions used in the Black-Scholes option model

The estimated fair value at the date of the grant for stock options utilizing the Black-Scholes option valuation model and the assumptions that were used in the Black-Scholes option model for fiscal year 2013 are as follows:

Estimated fair value of options at date of grant	$213,696
Black-Scholes model assumptions
Average expected life (years)	5
Average expected volatility factor	353.3%
Average risk-free interest rate	3.0%
Average expected dividend yields	$-0-