** Shares in Maersk MAERSKb.CO drop 6% after the Danish shipping group said one of the services in its Gemini network with Germany's Hapag-Lloyd HLAG.DE will resume sailing through the Suez Canal

** Hapag-Lloyd shares also fall around 3% after the announcement

** The joint decision comes following thorough assessments of the security situation in the Red Sea area, and marks a step towards a gradual return to the trans-Suez corridor, Maersk said

** Morningstar analyst Ben Slupecki says Red Sea rerouting has benefited container carriers by "artificially reducing supply" and lifting shipping prices

** Carriers' margins are heavily correlated with freight rates, as many costs are fixed, allowing extra revenue to flow through to profits, Slupecki says

** "It is unsurprising that shares fall on the return, given that it reverses this effect," Slupecki says

** Maersk shares are among the biggest fallers on the pan-European STOXX 600 index .STOXX

($1 = 6.5458 Danish crowns)