"LONDON — Oil prices quickly gave back early gains to close lower on Monday after investor concerns about Middle East tensions gave way to a continued focus on weaknesses in global economies.

Earlier in the day, a growing conflict between Saudi Arabia and Iran worried investors, sending oil prices higher during the European trading day.

In the past, a flare-up in the Middle East could send oil prices soaring, but investors these days seem mainly focused on a global glut of petroleum. With so much oil on the world market, even the biggest producer — Saudi Arabia — has only a limited ability to affect prices."

Stanley Reed reports for the New York Times January 4, 2016. [2]