  The valence orders at $T_a=125$ K and $T_b=105$ K in the cubic compound YbPd
have been investigated by $^{105}$Pd-nuclear magnetic resonance (NMR)
measurements. Significant decrease in the density of states at the Fermi energy
below $T_a$ is evident from the measurement of nuclear spin lattice relaxation
rate $1/T_1$, suggesting that the instabilities of Fermi surface are associated
with the transitions. Moreover we observed the unusual evolution of low-energy
fluctuations toward the valence transition at $T_a$ behind its drastic
first-order nature. The structural transition accompanying the valence order
may occur as a result of cooperative effect of Fermi surface and valence
instabilities.
