Viacom's ( VIAB) board of directors will soon be getting smaller.The media and entertainment conglomerate said two of the company's 17 directors won't run for re-election at next month's annual meeting. By not replacing them, Viacom -- which cut its board size last year as well -- says it will be getting closer to its "target size" of 14 directors. Like other high-profile companies, including rival Disney ( DIS), Viacom has said that a smaller board of directors -- presumably, a less unwieldy committee of corporate overseers -- is one element of improved corporate governance. Nine of the returning 15 directors qualify as independent, said Viacom, addressing another yardstick often used to assess the quality of corporate governance -- independent director majorities. Departing from the board will be Ivan Seidenberg, chairman and CEO of Verizon ( VZ), and William H. Gray III, CEO of The College Fund/United Negro College Fund. "Bill and Ivan have decided to leave our board in order to focus on other commitments," Viacom Chairman and CEO Sumner Redstone said in a statement. The departing directors "have served Viacom and its shareholders with distinction for many years and have been particularly instrumental during a period of great change and growth at the company," Redstone said. On Thursday, Viacom slipped 38 cents to $40.24.