Boxship charter rates are rising across the spectrum as thinning supply coincides with plans by liner operators to launch or upgrade new services.

Charter rates for the largest containerships of 8,500 teu have risen by $2,000 per day this month, while some modern feeder designs are reaping their best figures in recent years.

That is feeding the market for midsize vessels, where traditional panamax boxships are able to command double the premiums earned a year ago and are heading towards breaching the $10,000-per-day barrier.