We investigate the possibility that in the foreign exchange market uninformed speculators find it convenient to trade on noise in order to gain an informational advantage they can exploit in future. In a two-period model, we analyze the trade-off between the cost of the "informational investment" and the profits this brings about, studying the optimal manipulation strategy under different hypotheses on the activity of market participants. Our results give a possible explanation for the presence of noise trading in the foreign exchange market. (C) 2000 Elsevier Science Ltd. All rights reserved. JEL classification: D82; G14; G15.