Containerships are staying active into the final days of 2020 amid high cargo demand, port congestion and tight supply, according to a sector analysis.

The global inactive fleet stood at 147 ships carrying 600,173 teu, representing 2.5% of all boxships as of 21 December, Alphaliner's last weekly report for 2020 showed.

"Persistently strong cargo demand, a fairly high number of vessels waiting at anchorage to berth at congested ports and a general shortage of ships and box equipment combine to keep the global inactive containership fleet low — even as we near the end of the year," Alphaliner said.