Net assets at end June were US$11.5mln or 0.97p per share compared to 1.328p in December.
A US$3.1mln fall in the value of its direct investment portfolio was responsible for the dip and accounted for the majority of an interim loss of US$4.5mln.
During the period, Metal Tiger restructured its interest in the T3 joint venture in Botswana and acquired an 18% stake in KML, which is also exploring for copper in the country.
The outlook for copper remains bright, it said, given limitations on supply and the important role of copper in the global economy.
T3, a joint venture with Australian explorer MOD has the potential to become a world class copper asset, it added.
At the end of August, Metal Tiger raised £6.2m at a price of 2.8p per share.