The calculations of earnings per common share for the quarters and six-month periods ended June 30, 2021 and 2020 are as follows:

Quarter Ended

Six-Month Period Ended

June 30,

2021

2020

2021

2020

(In thousands, except per share information)

Net income

$

70,558

$

21,256

$

131,708

$

23,522

Less: Preferred stock dividends

(669)

(1,338)

Net income attributable to common stockholders

$

69,889

$

20,587

$

130,370

$

22,184

Weighted-Average Shares:

Average common shares outstanding

213,574

216,920

215,294

216,853

Average potential dilutive common shares

1,035

650

1,139

589

Average common shares outstanding - assuming dilution

214,609

217,570

216,433

217,442

Earnings per common share:

Basic

$

0.33

$

0.09

$

0.61

$

0.10

Diluted

$

0.33

$

0.09

$

0.60

$

0.10