The efficient markets hypothesis does not state that markets are efficient at everything. Rather, that they are efficient at processing information about what market prices should be.
The EMH then comes in three flavours, weak (which pretty much all economists sign up to), semi-strong and strong. The strong version insists that all information is already in market prices. Even private and secret stuff – because the people with the private and secret information will trade upon it and thereby move prices to reflect it.
OK, bit of a butchering of the theory but close enough for our jazz.
The strong, ahaha, implication of this is that there is no secret information possible which will enable you to beat the market.
The case shone an embarrassing spotlight on the DGSE’s decision to place about €23 million (£20.3 million) from a secret war chest it had squirrelled away since the First World War into investment funds, mainly in the luxury sector, which had racked up massive losses.
So, even the spies lose their money when they invest. There is no secret information which allows beating the market – the strong version of the EMH is correct.
Saly, this is not an exclusive answer, exclusive in it being the only possible blade to Occam’s shaving kit. Another possible answer is that spies, like all other bureaucrats, are just shite at investing. Tho’ that does rather boost that idea that markets are still efficient, given that bureaucracies are clearly worse.