Using data from one of the Internet’s leading price comparison sites for consumer
electronics products, we present evidence for the persistence of price dispersion for
36 homogeneous products. The markets for these products are “thick” with an
average of over 20 firms selling each product. We show that prices do not converge
to the “law of one price” even after an 18 month period. This finding is robust to
controls for differences in shipping charges and inventories.