 SAN ANTONIO--BUSINESS WIRE--NuStar Energy L.P. NYSE: NS today announced that its Board of Directors has declared a second quarter 2021 common unit distribution of 0.40 per unit. The second quarter common unit distribution will be paid on August 12, 2021 to holders of record as of August 6, 2021. NuStar Energy L.P.s Board of Directors also declared a second quarter 2021 Series A preferred unit distribution of 0.53125 per unit, a Series B preferred unit distribution of 0.47657 per unit an 