Apple could "double or potentially even triple" it share of the cellphone and computer markets in the next several years, argues Sterne Agee's Shaw Wu. In a new memo the analyst remarks that for all of Apple's success, the company still has only 4 to 5 percent of the cellphone market, and a similar share of computers, although that number jumps to 12 to 13 percent if counting the iPad in that category. China and the international market in general are said to be "underpenetrated opportunities" for sales.