Looks like the Justice Department is taking an interest in the pricing of e-books by major publishers. The Wall Street Journal’s Jeff Trachtenberg had the story yesterday, and the New York Times followed up this morning. DOJ is threatening a suit over the “agency model” of e-book pricing, in which the publisher sets the retail price and nobody is allowed to undercut it. Until a couple of years ago, e-books were sold under a “wholesale model,” in which the publisher sells for a set wholesale price, usually about half the “suggested” cover price, and retailers can discount however they like. (Physical books are still sold this way, which is why you frequently see an e-book that costs more than a paper one.)

DOJ is investigating Apple and five major publishers (curiously, the largest one of all, Random House, is not listed; at first they balked at the “agency model,”…