Markets are betting the Federal Reserve leaves rates unchanged at its September meeting, but Barclays Investment Bank Economist Robert Martin believes policymakers will pull the trigger next month, taking advantage of a "Goldilocks moment."
That is certainly a contrarian call. Market participants currently see just a 21 percent chance the Federal Open Market Committee will increase rates when it meets Sept. 20-21, according to the CME FedWatch Tool.
What makes Martin believe the FOMC will move in September is that Fed officials have recently said they expect at least one rate hike this year. Barclays is hanging its hat on the phrase "at least," he said.
"If you want to have the possibility of that 'at least' part of that coming true — you want to do more than one — the way we're thinking about it, it's a September [hike] or never," he told CNBC's "Squawk Box" on Wednesday.
Barclays believes Fed Chair Janet Yellen is becoming concerned about the Fed's credibility. If central bankers waits until December, they risk being delayed by some adverse economic event, Martin said. At that point, policymakers would have no more 2016 meetings to fall back on and make good on their forecast for one hike this year.
The market certainly appears wary of the Fed at present. A new CNBC survey found 60 percent of the 39 Wall Street respondents believe the Fed lacks a blueprint to make interest rate decisions.
Further, the economy and labor market are currently on better footing than in June, when the Fed left rates unchanged following a dismal May jobs report, Martin said. Barclays expects the August data to show employment gains of more than 200,000 for a third month in a row following two blockbuster reports in June and July.
"So long as financial markets remain stable and so long as the August employment report is solid, we see September as a 'Goldilocks' moment for the Fed to hike," he told CNBC.
If the Fed does not move in September, it will likely be because the FOMC has decided to put off raising rates until it meets its inflation target of 2 percent, he said. According to Barclays' inflation forecast, that would leave the Fed on hold not until December, but late next year.
The Fed has not raised its Fed funds rates since last December, when it lifted the benchmark by a quarter of a percent from near zero.
Markets could get a better view into the Fed's thinking when Yellen delivers a speech on Friday from the Fed's annual retreat in Jackson Hole, Wyoming.
Steven Rees, global head of equity strategy JPMorgan Private Bank, said Wednesday he doesn't expect any meaningful commentary to come out of the speech. JPMorgan Private Bank continues to believe the FOMC is most likely to raise rates at its December meeting, he told "Squawk Box."
Raymond James Chief Investment Strategist Jeffrey Saut also told "Squawk Box" a rate hike before the election remains unlikely.