The bulk of the literature has tested informational efficiency for
assets traded on regular markets but only rarely on clandestine
markets. In the latter case, empirical studies have been conducted
mainly on exchange markets, which have generally been found to
be efficient (Gupta, 1981; Booth and Mustafa, 1991; Huett et al.,
2014). In contrast to the existing literature, this paper focuses on
gold, a real and tangible asset, and analyzes the changes in informational
efficiency when the black market was replaced by an official
market in February 1948.