Are online auction markets efficient? An empirical study of market liquidity and abnormal returns

Technological advances have facilitated investment in collectibles through online auction markets, where information regarding product characteristics, current and historical prices, and product availability is available to millions of market participants. However, market inefficiencies may still exist, where prices do not reflect market information and where savvy speculators can profit. Using unit root and variance ratio tests, we examine 8538 rare stamp and 56,997 rare coin auctions to evaluate the efficiency of online markets. In particular, we study market liquidity, abnormal returns and weak-form efficiency. We find an inverse relationship between market efficiency and liquidity. Bidder competition intrinsic to liquidity increases the chances that uninformed bidders drive up item prices, leading to the observed market inefficiencies

Are Online Auction Markets Efficient? An Empirical Study of Market Liquidity and Abnormal Returns.

Under dynamic loading the stabilising effect of increased strain rate sensitivity of the material restrains neck formation in tension tests and leads to an increase in ductility. On the other hand the adiabatic character of the deformation process reduces the flow stress and promotes instability, localisation and adiabatic shear band initiation. Furthermore, the notch sensitivity of the material increases with increasing strain rate. Dynamic and quasi-static tension and compression tests were carried out on the age hardenable aluminium wrought alloy AA7075. There, dispers distributed precipitations are often the starting point for ductile fracture caused by impact due to the nucleation, growth and coalescence of voids and micro-cracks in case of tension. Neck formation under tensile loading and instabilities like shear bands in case of compression are discussed on the basis of the theory of imperfections under consideration of the increased strain rate sensitivity of the material and the adiabatic character of the deformation process at high strain rates. In case of tensile loading, tests with various notched geometries allowed the study of the influence of degree of multiaxiality. Through combination of experiment and simulation, the influence of strain rate on the local fracture strain could be determined for tensile and compression loading