Downtown Summerlin landlord Howard Hughes Holdings obtained a $300 million loan on the suburban Las Vegas development. The company said in an earnings release Thursday that it recently closed on a new five-year mortgage secured by the property. It did not say how it would use the proceeds, nor did it specify which aspects of Downtown Summerlin were put up as collateral for the loan. Downtown Summerlin’s centerpiece is the 106-acre outdoor mall at Sahara Avenue and the 215 Beltway. But the developer has said that, overall, Downtown Summerlin spans 400 acres and includes other projects near the popular retail-and-dining hub. Still, the company said in a presentation that the new $300 million in financing “highlights the strength of one of the portfolio’s highest-quality retail assets, reflecting solid operating performance and the successful transition and upgrade of tenants following the property’s 10-year anniversary.” The outdoor mall debuted in October 2014 .…