Investors in private prison operators appear to be preparing for a Hillary Clinton presidency on Tuesday; shares of Corrections Corp (CXW) and Geo Group (GEO) fell after the candidate criticized states' use of for profit prisons in her first debate with rival Donald TrumpCWX slid as much as 6.2%, on track for its biggest daily drop since Aug 18, when U.S. Justice Department announced plans to phase out use of privately operated prisons.GEO fell as much as 4% on track for its biggest daily decline since Aug 30"I'm glad that we're ending private prisons in the federal system; I want to see them ended in the state system," Clinton said according to a transcript from the debate with rival candidate Donald Trump. "You shouldn't have a profit motivation to fill prison cells with young Americans. So there are some positive ways we can work on this."About 7.9% of Geo's shares were sold short compared with 10.3% for Corrections Corp as of Sept 15This puts both co's short interest as pct of shares outstanding at the top of their 52-week rangesActually, it is a very rare case when I agree with Ms Clinton, private prisons have to be prohibited. But record shorts are begging for squeeze if Trump advances in polls. $CXW, CoreCivic, Inc. / 1440 $GEO, Geo Group Inc (The) REIT / 1440