Basic and diluted earnings per share are calculated as follows (in thousands, except per share amounts):


	Year Ended December 31,
	2022		2021		2020
Basic earnings per share
Numerator:


Net income attributable to Albemarle Corporation	$	2,689,816	$	123,672	$	375,764
Denominator:
Weighted-average common shares for basic earnings per share	117,120		115,841		106,402
Basic earnings per share	$	22.97	$	1.07	$	3.53
Diluted earnings per share
Numerator:


Net income attributable to Albemarle Corporation	$	2,689,816	$	123,672	$	375,764
Denominator:
Weighted-average common shares for basic earnings per share	117,120		115,841		106,402
Incremental shares under stock compensation plans	673		695		406
Weighted-average common shares for diluted earnings per share	117,793		116,536		106,808
Diluted earnings per share	$	22.84	$	1.06	$	3.52

Included in the calculation of basic earnings per share are unvested restricted stock awards that contain nonforfeitable rights to dividends. At December 31, 2022, there were 5,117 unvested shares of restricted stock awards outstanding.

We have the authority to issue 15 million shares of preferred stock in one or more classes or series. As of December 31, 2022, no shares of preferred stock have been issued.

On February 8, 2021, we completed an underwritten public offering of 8,496,773 shares of our common stock, par value $0.01 per share, at a price to the public of $153.00 per share. The Company also granted to the Underwriters an option to purchase up to an additional 1,274,509 shares for a period of 30 days, which was exercised. The total gross proceeds from this offering were approximately $1.5 billion, before deducting expenses, underwriting discounts and commissions.

In November 2016, our Board of Directors authorized an increase in the number of shares the Company is permitted to repurchase under our share repurchase program, pursuant to which the Company is now permitted to repurchase up to a maximum of 15 million shares, including those previously authorized but not yet repurchased.

There were no shares of the Company’s common stock repurchased during the year ended December 31, 2022, 2021 or 2020. As of December 31, 2022, there were 7,396,263 remaining shares available for repurchase under the Company’s authorized share repurchase program.