The world’s top 20 ocean carriers boosted their container ship fleets by 844,000 20-foot equivalent units in the past 12 months, intensifying competition even as they piled up large losses, according to Alphaliner.

The two largest lines, Maersk and Mediterranean Shipping Co., accounted for more than half the extra capacity, adding 232,000 TEUs and 218,000 TEUs respectively since July 2011, the container market analyst said.

The world fleet reached 16.53 million TEUs by July 1, of which 16.05 million TEUs consisted of fully cellular vessels. Total capacity grew 6.5 percent, with the top 20 carriers boosting their aggregate capacity by 6.4 percent.

Capacity additions ranged from 2 percent to more than 19 percent, while Chile’s CSAV and Israeli line Zim were the only top 20 carriers to cull capacity during the year.

Mitsui OSK, CSCL and COSCO, recorded the largest percentage increases of 19.4 percent, 18.2 percent and 16 percent, due to a combination of new vessel deliveries and the recovery of chartered-out capacity.

Maersk’s capacity grew 9.8 percent; MSC was up 10.9 percent. France’s CMA CGM, the world’s third ranked carrier, increased capacity by 4.4 percent, or 56,200 TEUs during the year.

CSAV, which has lost $1.5 billion since the beginning of 2011, slashed its fleet to 269,000 TEUs from 544,000 TEUs and a peak of 588,000 TEUs in the first quarter of 2011.

Zim, which lost $559 million in the period, trimmed its fleet by just 10,700 TEUs, but it does not have any near-term growth plans as it focuses on restoring its finances, Alphaliner noted.

Maersk operated a fleet of 2.61 million TEUs, with a 15.8 percent market share, as of July 3, followed by MSC at 2.22 million TEUs and 13.4 percent and CMA CGM with 1.34 million TEUs and 8.1 percent.

The Journal of Commerce Online