** Canadian drugmaker's U.S.-listed shares reverse course, now down 3.4 pct at $22.72
** Andrew Left taking new short stake in Valeant, The Street reported, calling the drugmaker an "obvious zero"
** Valeant had short interest of 8.9 pct as of June 30 and short squeeze indicator model at 98/100 (100 = most likely to have a short squeeze) - Thomson Reuters data
** Former Valeant CEO Michael Pearson sold nearly 5 mln shares and options for a total of $96.8 mln, CNBC reports, citing documents not made public yet (cnb.cx/29XNVcZ)
** Pearson left Valeant on May 2 after a year in which the company had drawn scrutiny for its sharp drug price increases, financial relationship with a specialty pharmacy and accounting practices
** Pearson got a $9 mln severance payment and agreed to a consulting agreement worth hundreds of thousands of dollars, according to a document filed with regulators
** Up to Tuesday's close, stock had fallen 77 pct this year