Global financial problems and the impact of UEFA's fair play regulations have been cited as causes for a fall in total payments between clubs in transfer and loan fees of US dollars 294million - around £190m - to $576m (£372m) on the same period last year, a decrease of 34%.
The figures are contained in FIFA's mid-year review of the international transfer market.
The report says: "This could suggest that the effects of the global recession - for instance, distressed corporate sponsors, restrictive bank lending policies and reduced overdraft facilities for clubs - are being felt in the international football transfer market.
"A further factor may be the high concentration of wealth in a relatively small number of associations; any reduction in spending in those few associations could have a disproportionately high impact on aggregate transfer fees worldwide.
"Finally, given the share of the European transfer market, the efforts of those clubs to bring themselves in line with the UEFA Financial Fair Play Regulations before the onset of sanctions for indebted clubs may contribute to a fall-off in transfer compensation rates."
Of the 4,973 transfers completed during the period, 708 involved Brazilian clubs with England second on the list on 326.
No association spent more than Russia, where clubs invested a total of $64.39m - £41.56m - while Brazilian clubs raked in $64.95m, or £41.92m, at the same time spending $62.02m (£40.03m).
English sides invested $55.43m (£35.78m) and recouped $58.83m (£37.97m).