Royal Caribbean Group is doubling down on expedition cruising despite facing the hardest, most uncertain times in its history as a result of the coronavirus pandemic.

The Richard Fain-led owner of 62 ships formerly known as Royal Caribbean Cruises has bought the remaining shares of Silversea Cruises, which holds six luxury expedition vessels.

Royal Caribbean assumed a two-thirds stake in the company two years ago for $1bn.

It acquired the rest of Silversea with 5.2m shares, or about 2.5%, of company stock from Heritage Cruise Holding.

Royal Caribbean shares, which trade on the Nasdaq Stock Market under the ticker symbol RCL, slipped 3.1% to $48 by early afternoon Tuesday.

"Silversea has been a great fit for our company from the very first day," Royal Caribbean chief executive Fain said in a statement.

"The cultures of the two organizations have proven to be harmonious, and guests have responded favorably to the combination."

Calls to New York-listed Royal Caribbean were not immediately returned.

Manfredi Lefebvre d'Ovidio will serve as chairman of Silversea, which the Lefebvre family founded in 1994 in a partnership with VShips.

Roberto Martinoli will remain the brand's president and CEO.

"Manfredi and Roberto have brought a fresh point of view to our company, as well as deep knowledge of their brand's unique audience," Fain said.

"Their skills – and Manfredi's inimitable style – will continue to play an important role in growing Silversea into the future."

Royal Caribbean in mid-May announced raising $3.3bn in debt finance amid a $1.44bn first-quarter loss amid the coronavirus pandemic — $1.3bn of which was recorded as Silversea vessel impairments.