Maike is one of China's largest copper importers, trading more than 1 million tonnes per year of copper at its peak.
It is also the only private enterprise that has agreed to join the action so far.
Fastmarkets reported early this month that the China Smelters Purchase Team (CSPT) had held an emergency meeting over the persistent backwardation and agreed to boost LME copper stock levels.
Jiangxi Copper, Tongling Nonferrous, China Copper, Xiangguang, Daye Nonferrous agreed to deliver copper cathode into LME warehouses in Asia, Fastmarkets confirmed.
Copper producers, which are taking long positions, could suffer massive hedging losses in rolling over their short positions under backwardation pressure.
The volume of aggregate deliveries from China and the date of arrival into warehouses remains unknown, as well as the feasibility of boarding a huge quantity of cathode amid a lack of vessel space.
Some shipments of thousands of tonnes of cathodes each are already arranged and have departed nonetheless, an operation manager of a major Chinese bank told Fastmarkets.
There are no LME deliverable warehouses in China despite advocacy from Maike chairman He Jinbi for several years.
This ongoing action is the first time ever for the Chinese copper sector to organize a collective export to the LME, whose copper on-warrant stocks once dropped below 15,000 tonnes, with the cash-to-November spread flaring to a backwardation of more than $1,000 per tonne one month ago.
While Trafigura admitted they were drawing copper from LME warehouses for delivery to clients in Asia and Europe, and had kept the exchange fully informed, the LME had to subsequently impose temporary measures to maintain market order, including a limit on the backwardation for tom-next contracts.
The inventory level has since rebounded, with 50,300 tonnes of deliverable copper as of Monday November 15.
Yet copper's spreads are still in backwardation, meaning the metal's spot price is higher than its future prices, since late September. The cash-to-three month spread was at $130 per tonne on Monday.
Ana de Liz in London contributed to this report.