Investors betting on a rebound in oil prices are nothing if not tenacious. They have poured the most money in more than four years into exchange-traded products that track oil as prices fell 18 percent this month. It’s the third consecutive month that the four biggest U.S. funds have received money, during which time futures have plunged 41 percent. “It’s a testament that after such a wild selloff people are more and more eager to step in and wait for this eventual rebound,” said Stoyan Bojinov, a Chicago-based analyst at ETF Database. “Oil looked cheap a month ago and it’s even cheaper today, that’s why we continue to see these inflows.” Oil prices have tumbled by half since June amid surging production and slower than expected demand growth. Output in the U.S. is the highest in three decades, and OPEC, responsible for about 40 percent of global supply, maintained […]