Shipping stocks have been on the rise as tensions in the Red Sea have reduced container availability — and have sent freight costs higher.

For example: Maersk (MAERSK-A.CO, MAERSK-B.CO) shares are up 37% since mid-December after Houthi rebel attacks forced the Danish carrier and other shipping companies to temporarily suspend or bypass the waters that connect to the Suez Canal — the shortest pathway between Asia and Europe.

The expectation of higher earnings from lower capacity and increased freight costs prompted analysts at Goldman Sachs and Bank of America to upgrade Maersk to Neutral from Underweight this week.

BofA analysts raised their price target on stock traded in Denmark from 8,800 to 15,100 Danish kroner, which is the equivalent of $1,290 to $2,215.

Goldman analysts increased their price target from 9,400 kroner to 13,000 kroner, or $1,380 to $1,909.

"Re-routing of vessels from Suez via the Cape in response to recent attacks on commercial vessels in the Red Sea is significantly reducing available space on container ships," wrote Goldman Sachs analyst Patrick Creuset in a note to investors.

The analyst estimates 70%-80% of vessels have rerouted as of last month, making their journeys 30% longer.

"Depending on how long the disruption lasts, it could lead to supply chain disruptions and significantly higher transport costs, especially on Asia-Europe trades," said the analyst.

Freight costs between Asia and Northern Europe have already soared 173% since mid-December, according to shipping data from Freightos Terminal.

German cargo giant Hapag-Lloyd (HLAG.DE), which has said it would avoid routing vessels through the Suez Canal, is up more than 65% since mid-December.

Shares of ZIM Integrated Shipping (ZIM), which serves East Mediterranean and Israeli ports, are up more than 70% during the same period.

Athens-based Star Bulk Carriers (SBLK) is also up 10% since mid-December while smaller vessel companies like Navios Maritime Partners and Global Ship Lease (GSL) have gained 16% and 14%, respectively.

Last month container companies announced they would temporarily pause Red Sea shipments amid Houthi rebel attacks on vessels spurred by the Hamas-Israel war.

On Tuesday Maersk said it would halt all cargo sails through the waterway until further notice.

Ines Ferre is a senior business reporter for Yahoo Finance. Follow her on Twitter at @ines_ferre.

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