NEW YORK ( TheStreet) -- Wells Fargo ( WFC), JPMorgan Chase ( JPM), SunTrust Banks ( STI) and City National Corp. ( CYN) are the banks best-positioned for a flatter U.S. Treasury yield curve now that the Federal Reserve has flattened it in a move dubbed " Operation Twist," according to a research report published Wednesday from Evercore Partners. There has been widespread speculation that the Fed will perform Operation Twist -- which would aim to raise short term interest rates while pushing down long-term rates, according to Evercore's note. The hope is that the move would attract foreign capital while keeping financing costs low, the report states. Overall, Operation Twist would be bad for banks long term because it would negatively impact net interest margins, which represent the difference between banks' cost of capital and what they can charge borrowers. However, it could offer short-benefits to banks by allowing them to get better returns on new cash coming onto the balance sheet from maturing loans. Those loans have been viewed by the market as having a high "reinvestment risk," because the cash must be reinvested at lower yields than the older loans had been generating. Banks likely to see the "greatest relief to downside reinvestment risk include those with larger portfolios but shorter durations and a higher concentration of securities maturing in three years," the report states. Examples of such banks include SVB Financial Group ( SVB), City National and Commerce Bancshares ( CBSH). Still, Wells, JPMorgan, SunTrust and City National are the best positioned for the new environment because they have "greater top-line diversification and above peer balance sheet growth prospects," according to the report. -- Written by Dan Freed in New York.