Carbon Natural Gas Company (OTCBB:CRBO) announced a private placement of share purchase agreement of 50,000 series B convertible preferred stock at $100 per share for gross proceeds of $5,000,000 with existing investor Yorktown Energy Partners IX, L.P., a fund managed by Yorktown Partners, L.L.C. on April 6, 2018. Each series B convertible preferred stock is entitled to receive cash dividends of 6% of the initial issue price of $100 per share per annum. The securities will be issued at par. The preference shares will be automatically converted into common shares at a conversion price of $8 per share, upon the effectiveness of an amendment to the company's certificate of incorporation to increase its authorized shares of common stock. The securities will be issued pursuant to Regulation D.