We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies—such as close pair counts , starburst counts , and the morphologically disturbed fraction—likely scale with luminosity , stellar mass , merger mass ratio , and redshift from z = 0 to z = 4 . We investigate both rate at which subhalos first enter the virial radius of a larger halo ( the “ infall rate ” ) , and the rate at which subhalos become destroyed , losing 90 \% of the mass they had at infall ( the “ destruction rate ” ) . For both merger rate definitions , we provide a simple ‘ universal ’ fitting formula that describes our derived merger rates for dark matter halos a function of dark halo mass , merger mass ratio , and redshift , and go on to predict galaxy merger rates using number density-matching to associate halos with galaxies . For example , we find that the instantaneous ( destruction ) merger rate of m / M > 0.3 mass ratio events into typical L \gtrsim f L _ { * } galaxies follows the simple relation dN / dt \simeq 0.03 ( 1 + f ) { Gyr } ^ { -1 } ( 1 + z ) ^ { 2.1 } . Despite the rapid increase in merger rate with redshift , only a small fraction of > 0.4 L _ { * } high-redshift galaxies ( \sim 3 \% at z = 2 ) should have experienced a major merger ( m / M > 0.3 ) in the very recent past ( t < 100 Myr ) . This suggests that short-lived , merger-induced bursts of star formation should not contribute significantly to the global star formation rate at early times , in agreement with several observational indications . In contrast , a fairly high fraction ( \sim 20 \% ) of those z = 2 galaxies should have experienced a morphologically transformative merger within a virial dynamical time ( \sim 500 Myr at z = 2 ) . We compare our results to observational merger rate estimates from both morphological indicators and pair-fraction based determinations between z = 0 - 2 and show that they are consistent with our predictions . However , we emphasize that great care must be made in these comparisons because the predicted observables depend very sensitively on galaxy luminosity , redshift , overall mass ratio , and uncertain relaxation timescales for merger remnants . We show that the majority of bright galaxies at z = 3 should have undergone a major merger ( > 0.3 ) in the previous 700 Myr and conclude that mergers almost certainly play an important role in delivering baryons and influencing the kinematic properties of Lyman Break Galaxies ( LBGs ) .