U.S. oil stumbled below $30 for the first time in 12 years to levels that threaten the survival of many U.S. shale firms, spur more belt-tightening by oil majors and spell more pain for crude-producing nations and regions. A seven-day losing streak fueled by concerns about a continued supply glut and fragile demand from China, the world’s No. 2 consumer, wiped out almost a fifth of crude prices CLc1 this year and 70 percent since mid-2014. Traders have all but given up attempting to predict where the new-year rout will end, with momentum-driven dealing and overwhelmingly bearish sentiment engulfing the market. Some analysts warned of $20 a barrel; Standard Chartered said fund selling may not relent until it reaches $10. And more of the world’s biggest energy companies are conceding that it may be many years before prices […]