Supersonic Aerospace International, LLC (SAI) was an American aerospace firm. The company was begun in 2001 by Michael Paulson, son of Gulfstream Aerospace founder Allen Paulson. It is working to build a supersonic business jet, the Quiet Supersonic Transport (QSST), though there has been no news of the project since the company's website went dormant in 2010.
References
Supersonic Aerospace International Wikipedia(Text) CC BY-SA