The fates of 1MDB bonds are diverging this month: those guaranteed by Abu Dhabi’s sovereign wealth fund have rallied, while notes with support from Malaysia’s own government have dropped. 1MDB's 4.4% 2023 notes, backed by the government, slumped 6.4% in May, set for the worst slide in 16 months. The fund’s 5.99% 2022 bonds, backed by Abu Dhabi’s International Petroleum Investment gained 1.9%. The contrast reflects growing investor concern about the Malaysian government backing as Najib grapples with an economy forecast to expand at the slowest pace in seven years amid a collapse in oil prices.