Money is pouring out of a popular investment tied to the oil market, a sign that a monthlong crude-price rally may be running out of gas. Exchange-traded funds that invest in U.S. oil futures, including the $3.1 billion United States Oil Fund LP, have registered about $2.7 billion of investor outflows this month, according to investment bank Macquarie Group Ltd. That reverses an inflow that started in January as oil prices tumbled. These ETFs took in roughly $6 billion this year through mid-March, when the U.S. oil benchmark hit a six-year low, according to Macquarie. Traders and analysts are closely watching weekly production and demand data for signs that the global glut of crude oil that sent prices swooning last year may be shrinking. They are also watching the ETF trends closely, because they say crude prices are vulnerable to a pullback following a 32% run-up since March […]