Oil prices have given up some of the gains achieved since the OPEC deal was agreed to in late November, and confidence in the buoyancy of crude prices is starting to falter. There are plenty of reasons why: U.S. shale is coming back; OPEC cuts led to higher prices in December, but have had little effect since then; crude and refined product inventories are still extraordinarily high; and speculative bets are looking overly optimistic at this point. But the major investment banks tracking oil markets are surprisingly steadfast in their predictions that the market is proceeding steadily towards balance, albeit at a slow pace. A roundup of the latest research notes from Wall Street banks show little fear of a major downslide in prices. Bloomberg points out that Goldman Sachs, Morgan Stanley, Bank of America and Citigroup are all sticking to their predictions of moderate price gains this year. […]