Two of the largest IPOs of the year, KBR (NYSE:KBR) and Hertz (NYSE:HTZ), both opened higher today in an IPO market that has performed extremely well during the past few months. KBR is trading up 23% in afternoon trading, while HTZ is trading up marginally at $15.06 after pricing its IPO at the top of its range. It is worth noting that KBR was a subsidiary of Halliburton, who will retain an 81 - 83% stake in the company, depending on the the underwriters' over-allotment actions. These IPOs come ahead of the much-anticipated Nymex IPO tomorrow, which remains heavily oversubscribed despite a 20% price hike and half million additional shares.