Check out which companies are making headlines after the bell Wednesday:
AMD - The chipmaker named Devinder Kumar as its new CFO. Kumar has been the company's interim CFO since September when Thomas Seifert resigned. Shares were slightly lower in extended-hours trading.
(Read More: Dow Surges 300 on 'Cliff' Deal, S&P Tops 1460)
Mellanox Technologies - The communications equipment manufacturer lowered its fourth-quarter revenue outlook to between $119 million and $121 million, citing challenging macroeconomic conditions, from a previous guidance of between $145 million and $150 million. Wall Street analysts expect the company to post sales of $148 million. Shares plunged nearly 20 percent in extended-hours trading after being temporarily halted.