Senior staff presented the model to policymakers at a retreat in Cyprus last week.
The rate is then seen rising again in December, possibly to 2%, taking it to the "neutral" territory which neither stimulates nor slows growth. And staff said this rate peak would be even lower if the ECB hoovered up some excess liquidity from the financial system - a reduction in its balance sheet often called quantitative tightening - the sources added.
Policymakers' key objection was that staff models have fared poorly in recent years so there was little confidence in an indicator that was so far below current market pricing, the sources said.
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In denial