Bank of America (NYSE:BAC) Downgrades Valero Energy (NYSE:VLO),

Bank of America (NYSE:BAC) took aim at the oil and gas operations sector, downgrading Valero Energy (NYSE:VLO), Frontier Oil (NYSE:FTO), Hess Corp. (NYSE:HES) and Wipro (NYSE:WIT).

All the companies were lowered from "Buy" to "Neutral."

Valero Energy closed Friday at $24.13, up $0.05, or 0.21 percent. Frontier Oil closed at $17.50, down $0.27, or 1.52 percent. Hess Corporation ended Friday at $78.65, down $0.79, or 0.99 percent. Wipro closed at $13.71, losing $1.27, or 8.48 percent.

Wipro had about 4 times the normal 3-month trading volume on Friday than they usually have.