We hold an economic interest and are the sole managing member in Spark HoldCo, with affiliates of our Founder and majority shareholder holding the remaining economic interests in Spark HoldCo. As a result, we consolidate the financial position and results of operations of Spark HoldCo, and reflect the economic interests owned by these affiliates as a non-controlling interest. The Company and affiliates owned the following economic interests in Spark HoldCo at December 31, 2020 and December 31, 2019, respectively.


	Year Ended December 31,
	2020		2019		2018

Net income (loss) allocated to non-controlling interest	$	44,277	$	7,604	$	(12,140)
Income tax expense allocated to non-controlling interest	5,349		1,841		1,066
Net income (loss) attributable to non-controlling interest	$	38,928	$	5,763	$	(13,206)

Holders of the Company's Class A common stock and Class B common stock vote together as a single class on all matters presented to our stockholders for their vote or approval, except as otherwise required by applicable law or by our certificate of incorporation.

Dividends declared for the Company's Class A common stock are reported as a reduction of retained earnings, or a reduction of additional paid in capital to the extent retained earnings are exhausted. During the years ended December 31, 2020, 2019, and 2018, we paid dividends on our Class A common stock of $10.6 million, $10.4 million, and $9.8 million. This dividend represented an annual rate of $0.725 per share on each share of Class A common stock.

In order to pay our stated dividends to holders of our Class A common stock, our subsidiary, Spark HoldCo is required to make corresponding distributions to holders of its units, including those holders that own our Class B common stock (our non-controlling interest holder). As a result, during the year ended December 31, 2020, Spark HoldCo made corresponding distributions of $15.1 million to our non-controlling interest holders.

On August 18, 2020, our Board of Directors authorized a share repurchase program of up to $20.0 million of Class A common stock through August 18, 2021. We are funding the program through available cash balances, our Senior Credit Facility and operating cash flows.

The shares of Class A common stock may be repurchased from time to time in the open market at prevailing market prices or in privately negotiated transactions based on ongoing assessments of capital needs, the market price of the stock, and other factors, including general market conditions. The repurchase program does not obligate us to acquire any particular amount of Class A common stock, may be modified or suspended at any time, and could be terminated prior to completion.

The Company has 20,000,000 shares of authorized preferred stock for which there are 3,707,256 shares issued and 3,567,543 shares outstanding at December 31, 2020 and 3,707,256 shares issued and 3,677,318 outstanding shares at December 31, 2019. See Note 6 "Preferred Stock" for a further discussion of preferred stock.

For the years ended December 31, 2020, 2019, and 2018, 469,811, 473,492, and 394,243, respectively of restricted stock units vested, with 292,879, 300,715, and 258,076, respectively of shares of common stock distributed to the holders of these units. Differences between shares vested and issued were a result of 176,932, 172,777, and 136,167 shares of common stock withheld by the Company to cover taxes owed on the vesting of such units.

In 2018, holders of Class B common stock exchanged 685,126 of their Spark HoldCo units (together with a corresponding number of shares of Class B common stock) for shares of Class A common stock at an exchange ratio of one share of Class A common stock for each Spark HoldCo unit (and corresponding share of Class B common stock) exchanged.

Basic earnings per share (“EPS”) is computed by dividing net income attributable to stockholders (the numerator) by the weighted-average number of Class A common shares outstanding for the period (the denominator). Class B common shares are not included in the calculation of basic earnings per share because they are not participating securities and have no economic interests. Diluted earnings per share is similarly calculated except that the denominator is increased by potentially dilutive securities.


	Year Ended December 31,
	2020		2019		2018
Net income (loss) attributable to Spark Energy, Inc. stockholders	$	29,290	$	8,450	$	(1,186)
Less: Dividend on Series A preferred stock	7,441		8,091		8,109
Net income (loss) attributable to stockholders of Class A common stock	$	21,849	$	359	$	(9,295)

Basic weighted average Class A common shares outstanding	14,555		14,286		13,390
Basic earnings (loss) per share attributable to stockholders	$	1.50	$	0.03	$	(0.69)

Net income (loss) attributable to stockholders of Class A common stock	$	21,849	$	359	$	(9,295)


Diluted net income (loss) attributable to stockholders of Class A common stock	$	21,849	$	359	$	(9,295)

Basic weighted average Class A common shares outstanding	14,555		14,286		13,390


Effect of dilutive restricted stock units	160		282		—
Diluted weighted average shares outstanding	14,715		14,568		13,390

Diluted earnings (loss) per share attributable to stockholders	$	1.48	$	0.02	$	(0.69)

The computation of diluted earnings per share for the year ended December 31, 2020 excludes 20.8 million shares of Class B common stock because the effect of their conversion was antidilutive. The Company's outstanding shares of Series A Preferred Stock were not included in the calculation of diluted earnings per share because they contain only contingent redemption provisions that have not occurred.

Spark HoldCo is a variable interest entity due to its lack of rights to participate in significant financial and operating decisions and its inability to dissolve or otherwise remove its management. Spark HoldCo owns all of the outstanding membership interests in each of our operating subsidiaries. We are the sole managing member of Spark HoldCo, manage Spark HoldCo's operating subsidiaries through this managing membership interest, and are considered the primary beneficiary of Spark HoldCo. The assets of Spark HoldCo cannot be used to settle our obligations except through distributions to us, and the liabilities of Spark HoldCo cannot be settled by us except through contributions to Spark HoldCo. The following table includes the carrying amounts and classification of the assets and liabilities of Spark HoldCo that are included in our consolidated balance sheet as of December 31, 2020 and 2019 (in thousands):