Tickets for the eight-day trip including the dive to the Titanic wreckage can be purchased for $250,000.
Among the people missing is 58-year-old British billionaire Hamish Harding.
OceanGate have since released a statement thanking all agencies for assisting with the search.
“We are deeply thankful for the extensive assistance we have received from several government agencies and deep sea companies in our efforts to re-establish contact with the submersible,” the company said.
The submersible is believed to be carrying one pilot, three guests and a content expert.
The vessel is comparable to the size of a truck and takes around eight hours to complete the dive including descent and ascent.
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