Energy stocks tumble as Greece weighs on markets By: MarketWatch April 27, 2010 at 13:34 PM EDT Oil and gas stocks fell Tuesday as Greece and Portugal's deepening economic problems sent shudders through global currency and equities markets. Read More >> Related Stocks: Anadarko Petroleum BP Plc ADR Natl Oilwell Varco Standard & Poors 500 Transocean Ltd Valero Energy