  The effect of dark matter/energy on gravitational time advancement (negative
effective time delay) has been investigated considering few dark energy/matter
models including cosmological constant. It is found that dark energy gives only
(positive) gravitational time delay irrespective of the position of the
observer whereas pure Schwarzschild geometry leads to gravitational time
advancement when the observer is situated at relatively stronger gravitational
field point in the light trajectory. Consequently, there will be no time
advancement effect at all at radial distances where gravitational field due to
dark energy is stronger than the gravitational field of Schwarzschild geometry.
