This allows shipping lines with a combined market share of less than 30 per cent to enter into agreements to provide joint services. Such agreements allow carriers to work together to achieve economies of scale.
This regulation was due to expire next year, and questions had been raised whether container lines needed their own set of rules rather than be treated the same way as most other industries.
The decision was announced in light of China's recent decision to ban the P3 Network proposed by Maersk Line, Mediterranean Shipping Co and CMA CGM, even though regulators in both the US and Europe said they would not block the alliance.
The commission, after public consultation, said the exemption had worked well, providing legal certainty to agreements, which had brought benefits to customers and "did not unduly distort competition".
But calls for the limit to rise to 35 per cent of market share were rejected. Limits went from 35 to 30 per cent after joint rate-fixing was prohibited in 2008. While opposed to price-fixing, the commission favours co-operation to reduce costs.