ATP Commences Public Offering

ATP O&G has commenced a public offering of approximately $150 million of convertible perpetual preferred stock. The underwriters for the offering will also have a 30-day option to purchase up to 225,000 additional shares of convertible perpetual preferred stock to cover any over-allotments. We intend to use a portion of the net proceeds of this offering to pay the cost of a capped call transaction to cover all shares convertible in this transaction and our outstanding preferred shares, 13.1 million shares. The capped call transaction can prevent any dilution of outstanding common shares as long as the share price is below $27.50.

The convertible perpetual preferred stock has a liquidation preference of $100 per share and will be convertible into shares of ATP common stock at a $22.20 conversion price. ATP intends to use the net proceeds from this offering to fund capital expenditures and for general corporate purposes.

The offering will be made under the Company’s existing shelf registration statement filed with the Securities and Exchange Commission (“SEC”). This announcement is neither an offer to sell nor a solicitation of an offer to buy any securities and shall not constitute an offer, solicitation or sale in any jurisdiction in which such offer, solicitation or sale would be unlawful. Any offers of the shares will be made exclusively by means of a prospectus supplement and accompanying prospectus.

Credit Suisse Securities (USA) LLC will act as book-running manager for the offering. A copy of the preliminary prospectus supplement and related base prospectus for the offering may be obtained on the SEC website at Alternatively, the underwriter will arrange to send you the preliminary prospectus supplement and related base prospectus if you request them by contacting Credit Suisse Securities (USA) LLC, Prospectus Department, One Madison Avenue, New York, NY 10010.