  We establish a connection between tree-level superamplitudes in ABJM theory
and leading singularities associated to special three-particle cuts of one-loop
superamplitudes where one of the tree amplitudes entering the cut is a
four-point amplitude. Using these relations, we show that certain intriguing
similarities between one-loop and tree-level superamplitudes observed recently
become completely manifest. This connection is reminiscent of a similar
relation in the maximally supersymmetric gauge theory in four dimensions, where
the sum of two-mass hard and one-mass box coefficients of a one-loop amplitude
equals the corresponding tree-level amplitude. As an application, we present a
very simple re-derivation of the six-point superamplitude and calculate the
eight-point superamplitude at one loop in ABJM theory.
