SandRidge Mississippian Trust I, a newly-formed trust that holds royalty interests in 37 producing and 123 development wells, filed on Thursday with the SEC to raise up to $250 million in an initial public offering. The Austin, TX-based company, was organized in 2010 and plans to list on the NYSE under the symbol SDT. Raymond James and Morgan Stanley are set to be the lead underwriters on the deal. No pricing terms were disclosed.