The Nasdaq-quoted owner said Southern Cross will purchase$220m of new common stock at $2.00 per share giving it control of 78.38% of thecompany.
The agreement is subject to certain conditions including awaiver of repurchase rights by holders of the company's convertible senior notesdue 2017.
Ultrapetrol expects the deal to close in December if all conditionsare met.
A group of shareholders led by the Menendez family havesecured an agreement giving them the right to buy up to a 14.6% chunk of the SouthernCross holding in Ultrapetrol if the private equity firm achieves certaininvestment returns and other conditions are met.
The deal also entitles them to a share of Southern Cross'returns above a particular threshold.
Felipe Menendez, Ultrapetrol's CEO, said: "We arepleased to have entered into this transaction which enables us to continue withthe implementation of our growth plan and strengthens our balance sheet.
“Southern Cross Group has strong leadership capabilities anda successful track record of partnering with companies that operate in LatinAmerica."
The third quarter of last year was the last time that Ultrapetrolreported a profit.
Its shares spent over 30 days languishing below the $1threshold before regaining compliance in September.
Units will begin trading in New York today at $1.50 apiece.
While the company is incorporated in the Bahamas, itsheadquarters are in Buenos Aires, where it oversees a fleet of nearly 700barges and pushboats in addition to a shipyard in Punta Alvear.
Ultrapetrol is also involved in the offshore marketthrough its subsidiary UP Offshore.
