A global glut and collapsing Chinese demand have received most of the blame for the 60 percent slump in iron ore prices over the past year. But one group of traders has also played a key role in pushing prices lower – speculators and fund managers. Money managers have almost doubled their short positions in iron ore futures and options on the New York Mercantile Exchange (Nymex) since the start of 2015, while other large speculators have increased their short bets by 150 percent, data from the Commodity Futures Trading Commission shows. The net effect has been a more than 170 percent jump in total Nymex iron ore futures open interest, just as prices fell more than a third to less than $50 per tonne.
