Navigator Holdings, which owns and operates the world's largest fleet of handysize liquefied gas carriers, filed on Thursday with the SEC to raise up to $200 million in an initial public offering. The London, United Kingdom-based company, which was founded in 1997 and booked $183 million in sales for the 12 months ended June 30, 2013, plans to list on the NYSE under the symbol NVGS. Navigator Holdings initially filed confidentially on July 18, 2013. Jefferies and Morgan Stanley are the joint bookrunners on the deal. No pricing terms were disclosed.