UDR has an effective registration statement that allows the Company to sell an undetermined number of debt and equity securities as defined in the prospectus. The Company had the ability to issue 350.0 million shares of common stock and 50.0 million shares of preferred shares as of December 31, 2019.

The following table presents the changes in the Company’s issued and outstanding shares of common and preferred stock for the years ended December 31, 2019, 2018 and 2017 (shares in thousands)

The Company has an equity distribution agreement which allows it from time to time, through its sales agents, to offer and sell up to 20.0 million shares of its common stock. Sales of such shares will be made by means of ordinary brokers’ transactions on the NYSE at market prices. In July 2017, the Company updated its equity distribution agreement to also permit the entry into separate forward sales agreements to or through its forward purchasers. As of December 31, 2019, 11.7 million shares were available for sale under the continuous equity program.

During the year ended December 31, 2019, the Company entered into the following equity transactions for our common stock:

Distributions are subject to the approval of the Board of Directors and are dependent upon our strategy, financial condition and operating results. UDR’s common distributions for the years ended December 31, 2019, 2018, and 2017 totaled $1.37, $1.29, and $1.24 per share, respectively.

Preferred Stock

The Series E Cumulative Convertible Preferred Stock (“Series E”) has no stated par value and a liquidation preference of $16.61 per share. Subject to certain adjustments and conditions, each share of the Series E is convertible at any time at the holder’s option into one share of our common stock prior to a “Special Dividend” declared in 2008 (1.083 shares after the Special Dividend). The holders of the Series E are entitled to vote on an as-converted basis as a single class in combination with the holders of common stock at any meeting of our stockholders for the election of directors or for any other purpose on which the holders of common stock are entitled to vote. The Series E has no stated maturity and is not subject to any sinking fund or any mandatory redemption.

Distributions declared on the Series E for the years ended December 31, 2019, 2018, and 2017 were $1.48, $1.40, and $1.33 per share, respectively. The Series E is not listed on any exchange. At December 31, 2019 and 2018, a total of 2,780,994 shares of the Series E were outstanding.

UDR is authorized to issue up to 20.0 million shares of the Series F Preferred Stock (“Series F”). The Series F may be purchased by holders of OP Units and DownREIT Units, at a purchase price of $0.0001 per share. OP/DownREIT Unitholders are entitled to subscribe for and purchase one share of UDR’s Series F for each OP/DownREIT Unit held. During the years ended December 31, 2019 and 2018, 1.1 million and less than 0.1 million of the Series F shares were forfeited upon the conversion of OP Units and DownREIT Units into Company common stock, respectively.

At December 31, 2019 and 2018, a total of 14.7 million and 15.8 million shares, respectively, of the Series F were outstanding with an aggregate purchase value of $1,469 and $1,580, respectively. Holders of the Series F are entitled to one vote for each share of the Series F they hold, voting together with the holders of our common stock, on each matter submitted to a vote of security holders at a meeting of our stockholders. The Series F does not entitle its holders to dividends or any other rights, privileges or preferences.

Distribution Reinvestment and Stock Purchase Plan

UDR’s Distribution Reinvestment and Stock Purchase Plan (the “Stock Purchase Plan”) allows common and preferred stockholders the opportunity to purchase, through the reinvestment of cash dividends and by making additional cash payments, additional shares of UDR’s common stock. From inception through December 31, 2008, shareholders have elected to utilize the Stock Purchase Plan to reinvest their distribution for the equivalent of 10.0 million shares of Company common stock. Shares in the amount of 11.0 million were reserved for issuance under the Stock Purchase Plan as of December 31, 2019. During the year ended December 31, 2019, UDR acquired all shares issued through the open market.