DryShips announced Thursday that it had completed its ATM equity offering, resulting in gross proceeds of roughly $500 million.

Following completion of the program, DryShips said, the company has about 185 million common shares outstanding. Merrill Lynch ( MER) was the sales agent in the offering.

"We believe the primary equity that we have raised has significantly improved our balance sheet and liquidity, and will enable us to continue reducing our debt obligations while also allowing us to take advantage of future growth opportunities," said DryShips CEO George Economou in a statement.

DryShips shares, which closed Thursday up 5.3% at $5.55, were rising 4.5% to $5.80 in extended trading.

As originally published, this article contained an error. The article originally misstated the number of shares DryShips would have outstanding after completing its equity offering. TheStreet.com regrets the error.