UPDATE 1-RESEARCH ALERT-BofA assumes coverage of 5 oil refiners

(Adds details)

Sept 11 (Reuters) - Banc of America Securities assumed coverage of five oil refiners on Tuesday and said it was "neutral" on the sector due to near-term risks to gasoline inventories.

BofA analyst Ari Raivetz downgraded independent refiner Sunoco Inc (SUN.N) to "neutral" from "buy," saying the company's net margin per barrel was almost $2.50 below its closest peer.

He expects this trend to continue well into the future given Sunoco's lack of relative refinery complexity and disadvantaged geographic location, among other factors. Raivetz lowered his price target on the stock to $65 from $90.

He upgraded Frontier Oil Corp (FTO.N) and Tesoro Corp (TSO.N) to "buy" from "neutral." Raivetz raised the price target on Frontier Oil to $50 from $31, and on Tesoro to $62 from $60.

Raivetz said Frontier Oil, which has assets ideally located to access cheap Canadian oil sands production, is the "most profitable refiner" in his coverage group.

Raivetz kept a "neutral" rating on Valero Energy Corp (VLO.N) and a "sell" rating on Western Refining Inc (WNR.N). (Reporting by Bhaswati Mukhopadhyay in Bangalore)