novel technologies in particular, has experienced extreme price and volume fluctuations in recent years. Continued market fluctuations could result in further volatility in the price at which our Common Stock may trade, which could cause its value to decline. To the extent we seek to raise capital in the future through the issuance of equity, those efforts could be limited or hindered by low and/or volatile market prices for our Common Stock.
We do not now meet the initial listing standards of the Nasdaq Stock Market or any other national securities exchange. We presently anticipate that our Common Stock will continue to be quoted on the OTCQB or another over-the-counter quotation system. In those venues, our stockholders may find it difficult to obtain accurate quotations as to the market value of their shares of our Common Stock and may find few buyers to purchase their stock and few market makers to support its price.
A more active market for our Common Stock may never develop. As a result, investors must bear the economic risk of holding their shares of our Common Stock for an indefinite period of time.
Our Common Stock is a “penny stock.”
The SEC has adopted regulations that generally define “penny stock” as an equity security that has a market price of less than $5.00 per share, subject to specific exemptions. The market price of our Common Stock is and is expected to continue to be in the near term, less than $5.00 per share and is therefore a “penny stock.” Brokers and dealers effecting transactions in “penny stock” must disclose certain information concerning the transaction, obtain a written agreement from the purchaser and determine that the purchaser is reasonably suitable to purchase the securities. Those rules may restrict the ability of brokers or dealers to sell our Common Stock and may affect the ability of our stockholders to sell their shares of our Common Stock. In addition, if our Common Stock continues to be quoted on the OTCQB as we expect, then our stockholders may find it difficult to obtain accurate quotations for our stock and may find few buyers to purchase our stock and few market makers to support its price.
If we issue additional shares in the future, including issuances of shares upon exercise of the Series K Warrants, Placement Agent Warrants, Series J Warrants, Series I Warrants, 2019 Placement Agent Warrants, Series H Warrants, Series G Warrants, Series F Warrants, Series E Warrants and our Series 1 and Series 2 Convertible Notes, our existing stockholders will be diluted.
As of September 30, 2021, our articles of incorporation authorize the issuance of up to 800,000,000 shares of Common Stock.
In connection with the 2021 Private Placement Financing, we issued to the investors in the 2021 Private Placement Financing an aggregate of 43,125,004 shares of Common Stock and Series K Warrants to acquire up to an additional 32,343,754 shares of Common Stock at an exercise price of $0.17 per share. In addition, we also issued designees of the Placement Agent Placement Agent Warrants to acquire up to 3,234,375 shares of Common Stock at an exercise price of $0.20 per share. As of December 16, 2021, up to 32,343,754 shares may be acquired upon the exercise of the Series K Warrants and up to 3,234,375 shares may be acquired upon the exercise of the Placement Agent Warrants.
In June 2020, we issued certain of holders of our Series D Warrants Series J Warrants to acquire up to 3,886,364 shares of our Common Stock at an initial exercise price of $0.25 per share as consideration for those holders exercising their Series D Warrants in full to acquire 5,181,819 shares of our Common Stock at $0.18 per share. As of December 16, 2021, up to 3,375,000 shares may be acquired upon the exercise of the Series J Warrants.
In connection with the October 2019 Financing that closed on October 18, 2019, we issued an aggregate of 14,285,714 shares of our Common Stock, which equaled approximately 8% of the 173,577,233 shares of our Common Stock that were issued and outstanding immediately prior to the commencement of the October 2019 Financing. Upon the closing of the October 2019 Financing, we also issued Series I Warrants to acquire up to an additional 14,285,714 shares of our Common Stock at an initial exercise price of $0.22 per share and additional warrants to acquire up to an additional 1,071,429 shares of our Common Stock at an initial exercise price of $0.21875 per share to designees of the Placement Agent (the “2019 Placement Agent Warrants”). As of December 16, 2021, up to 14,285,714 shares may be acquired upon the exercise of the Series I Warrants and up to 1,071,429 shares may be acquired upon the exercise of the 2019 Placement Agent Warrants.
In connection with the financing that closed on May 14, 2019 (the “2019 Financing”), we issued an aggregate of 8,615,384 shares of our Common Stock, which equaled approximately 5% of the 164,961,849 shares of our Common Stock that were issued and outstanding immediately prior to the commencement of the 2019 Financing. Upon the closing of the 2019 Financing, we also issued Series H Warrants to acquire up to an additional 8,615,384 shares of our Common Stock at an initial exercise price of $0.40 per share. As of December 16, 2021, up to 8,615,384 shares may be acquired upon the exercise of the Series H Warrants.