“Something potentially… seismic” happened last week, says Jeremy Warner in The Sunday Telegraph. Oil prices slumped sharply. US WTI futures lost 7% and tumbled through the $50-a-barrel mark. Brent crude, the other key benchmark, has also slipped to a four-month low. Bullish speculators had piled into oil futures, so when the trend changed they all rushed for the exit, exacerbating the downdraft. But the underlying problem is that the glut everyone thought would be shrinking by now just isn’t. “There is little to suggest as yet that… market tightening has begun,” as Commerzbank puts it.