Oil prices have risen sharply over the last few months. Normally, that's a recipe for a drilling frenzy from U.S. oil producers. But something strange is happening, or rather, not happening.
"U.S. producers are actually being restrained at the moment," says Helima Croft, global head of commodities strategy at RBC Capital Markets. "They are trying to be disciplined."
Oil companies are under a lot of pressure to keep their production down. And the call is coming from inside the house: it's oil investors who are pushing for companies to pump less oil.