A Chequer-Board of Nights and Days

Oil dropped under $60 to a six-month low on Monday as abundant supplies in top consumer the United States and fears that slower U.S. economic growth would stunt demand for fuel extended a price retreat.

U.S. crude has fallen nearly $19 from its mid-July peak of $78.40, its biggest slide in more than 15 years. The 24 percent decline was set off as investors' concern faded over Iran and the Atlantic hurricane season proved unexpectedly mild.

The rout deepened last week as speculators fretted over slowing economic growth in the world's top consumer and hedge fund Amaranth Advisors registered billions of dollars in losses.

U.S. crude was trading down 75 cents at $59.80 by 1444 GMT. London Brent was 93 cents lower at $59.48.

"You have summer support unwinding, very bad product market support and on top of that the U.S. economic slowdown is becoming more compelling," said Eoin O'Callaghan of BNP Paribas.

I kind of doubt that last explanation will hold in the long term, but the general discussion appears to be around issues of supply and demand, which do more to explain the fluctuations in oil prices than any conspiracy theory could hope to do.