A U.S. strike is likely for three reasons: 1) Large U.S. military buildup in region, 2) Gap between U.S. and Iranian positions unlikely to close, 3) Trump tends to follow through on foreign policy threats. A lasting oil spike requires: 1) Iranian regime survives initial strike, 2) Iran retaliates significantly (not symbolically), 3) Retaliation targets oil production/transport. These are not guaranteed.

Closure is a big risk - 20% of global oil flows through. If it happens, rule of thumb: lose 1% of supply = 4% price increase. Lose 20% = 80% spike, taking oil to ~$108/barrel.

About $3 per barrel, based on movements between oil, gold, and equity prices.