However, oil prices gained after the wave of arrests in Saudi Arabia of princes, businessmen and government ministers. Shortly after European markets opened West Texas Intermediate crude oil was up by 0.7% at $56.01 a barrel, a level last reached in 2015. Brent crude was up 0.8% at $62.54 a barrel. Oil, gas and commodity-focused stocks were among the best performing in Europe, with Tullow Oil TUWOY 1.61% up 3%, and BHP Billiton and Anglo American each up by more than 2%. The oil-and-gas sector of the Stoxx Europe 600 was up 0.2%. Banking stocks were among the worst performing in Europe, with the sector down 0.8%. Saudi Prince al-Waleed bin Talal was one of those detained in Saudi Araba. U.S. equity futures were roughly flat, with S&P 500 futures down by less than 0.1% in early European trading, with investors also keeping a close eye on tax-reform plans. […]