Pimco is still hawking its "new neutral" expectations for interest rates to stay lower for longer, but some analysts are starting to express doubt.
The argument from Pimco can be compelling.
"There isn't as much credit growth as there used to be. So when the [Federal Reserve] decides it's time to raise interest rates, they'll say there isn't a lot of credit growth to rein in," meaning they don't need to raise rates as high as in the past, Tony Crescenzi, portfolio manager at Pimco, told CNBC.
"The neutral policy rate where the Fed is neither putting its foot on the pedal giving it gas or putting on the brakes is likely now 2 percent instead of the old 4 percent," he said.
Pimco expects this will create a Goldilocks-style not-too-hot, not-too-cold porridge keeping markets on an even keel.
"Because policy rates will be stable [and] because interest rate volatility will be low, it'll be supportive of equities and credit markets," Crescenzi said. "Credit spreads can stay tight [and] equity valuations can stay high."
But some analysts question whether interest rates really will set a new, lower neutral.