UPDATE 1-Investors pull billions from stock funds for 3rd straight week -Lipper

(New throughout; adds data on mutual funds and ETFs, analyst quote) By Trevor Hunnicutt NEW YORK, Jan 21 (Reuters) - Investors yanked $5.2 billion from stock mutual funds in the United States during the sharply volatile week that ended Jan. 20, Lipper data showed on Thursday, marking three consecutive weeks of outflows. World stocks and corporate credits came under severe selling pressure as oil sank below $27 a barrel to its lowest level since 2003. High-yield junk bond fund