A massive jump in spot rates may not prove sustainable because carriers are “artificially” inflating spot rates ahead of negotiations for long-term contracts, say analysts.

The reaction came after container spot rates on the transpacific recorded their biggest jump of the year.

Container freight rates from Asia to the US West Coast rose 70% to $1,721 per 40-foot equivalent unit (feu) container in the week ending 18 April, a level not seen since last November.