Recently, GAMCO reported upping its stake s in Chemtura Corp (NYSE: CHMT ) and The Pep Boys – Manny, Moe & Jack (NYSE: PBY ). GAMCO reported holding 4.54 million Chemtura Corp (NYSE:CHMT) shares, which represent an increase from 4.33 million shares the fund held previously. The fund boosted its position in The Pep Boys – Manny, Moe & Jack (NYSE:PBY) to 6.16 million shares from 5.58 million shares reported previously. The stake is equivalent to 11.56% of common stock outstanding.