STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Stock-based compensation expense

Stock-based compensation expense was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
	($ in millions)
Stock-based compensation	$	7.2	$	4.3	$	11.9	$	6.3
Mark-to-market adjustments	6.0		(0.1)		14.1		(3.1)
Total expense	$	13.2	$	4.2	$	26.0	$	3.2

Schedule of fair value of stock options granted valuation assumptions

The fair value of each stock option granted, which typically vests ratably over three years, but not less than one year, was estimated on the date of grant, using the Black-Scholes option-pricing model with the following weighted-average assumptions:

Grant date	2021
Dividend yield	2.76		%
Risk-free interest rate	0.94		%
Expected volatility of Olin common stock	44		%
Expected life (years)	7.0
Weighted-average grant fair value (per option)	$	9.91
Weighted-average exercise price	$	28.99
Options granted	1,094,700

Schedule of fair value of performance share awards granted valuation assumptions

The fair value of each performance stock award based on TSR was estimated on the date of grant, using a Monte Carlo simulation model with the following weighted average assumptions:

Grant date	2021
Risk-free interest rate	0.23		%
Expected volatility of Olin common stock	55		%
Expected average volatility of peer companies	50		%
Average correlation coefficient of peer companies	0.50
Expected life (years)	3.0
Grant date fair value (TSR based award)	$	39.96
Grant date fair value (net income based award)	$	28.99
Awards granted	248,700