...NEW YORK (Standard & Poor's) May 18, 2015--Standard & Poor's Ratings Services assigned its '##-' rating and stable outlook to Port Authority of New York & New Jersey's (PANYNJ) pro forma $500 million 191st series consolidated bonds and affirmed its '##-' rating, with a stable outlook, on PANYNJ's existing consolidated bonds. The rating service also affirmed its 'A-1+' short-term rating on the authority's commercial paper notes, as of May 1, 2015. In addition, Standard & Poor's affirmed its '##-' rating, with a stable outlook, on New York Liberty Development Corp.'s series 1WTC-2011 liberty revenue bonds, which are on par with all of PANYNJ's consolidated bonds. Finally, the rating service affirmed its 'A+' rating, with a stable outlook, on PANYNJ's series 2011 liberty revenue bonds, issued for the 4 World Trade Center (WTC) LLC project, paid from the authority's consolidated bond reserve fund. "We could lower the ratings if the authority's liquidity and financial margins were to erode considerably,"...