HK shares plunge 12.7 pct in biggest drop since '97 Reuters - 1 hour 6 minutes ago * HSI falls below 12,000 points; lowest since mid-2004 ADVERTISEMENT * HSI posts biggest one-day drop since 1997 * HSBC mauled by crisis fears * Energy stocks slump amid extended pullback in crude prices By Jun Ebias HONG KONG, Oct 27 - Hong Kong shares plunged 12.7 percent in their biggest single-day drop since 1997 on Monday, led by blue-chip heavyweight HSBC <0005.HK>, as fears of a global recession hammered Asian financial markets. The benchmark Hang Seng Index <.HSI> closed down 1,602.54 points...