The purpose of the warrants was to increase the value of Kinder Morgan's buyout offer for El Paso common stock without Kinder having to come up with more cash immediately, and thus having to incur additional debt to fund the buyout. If Kinder Morgan wins regarding the deal, then former El Paso shareholder's also win. The warrants were an extra inducement for El Paso's board of directors to accept the buyout offer. KMI was trading in the mid $26 range on the trading day prior to the announced buyout acceptance.
KMI warrants expiring 2/18/2017 were issued in connection with the multiple security merger of El Paso Corp into Kinder Morgan Inc on 5/25/2012. They last traded at $4,44 as ticker KMI' (That's a single apostrophe after the KMI for the warrant ticker.)