The cash will be used to reduce its net debt.
Chief operating officer Rita Whittington told investors the firm was focused on ensuring it was well placed to withstand an extended period of the current oil price downturn and also any further deterioration in market conditions.
"A comprehensive review is underway to realign our cost base with today’s markets and in tandem with this, the net proceeds of the placing will be used to reduce net debt and further strengthen Magnolia’s balance sheet.
"While we have no control over the direction of the oil price or how long the current downturn will last, we are taking every measure to ensure Magnolia is well placed for when sentiment and activity recovers.”
The company issued around 214.2 mln shares at 0.14 pence per share. The shares on Friday closed at 0.19p.
The US onshore oil and gas group added eight new wells to its portfolio in its latest quarter, taking the total in production where it has a stake to 210.
Shares today are down around 21% at 0.15p.