A managed float is a regime in which the exchange rate is broadly market-determined but the authorities intervene from time to time, buying or selling their own currency to influence its path without committing to any published level. It is sometimes called a dirty float, and it sits between a free float and a peg rather than being a distinct third thing.
What separates it from a free float is discretion rather than rules: there is no announced band to trade against and usually no stated trigger, so an intervention is identified after the fact from the central bank's reserve reporting or from its own statements. What separates it from a peg is that nothing is defended — the authorities are influencing a direction or a pace, not holding a number. For a pair quoted under this regime that means ordinary market behaviour interrupted, occasionally, by flow that has nothing to do with the rest of the market.
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Guide
How to Check the Way a Currency Is Managed
The regime behind a currency is published, not inferred. The four primary sources that say how a rate is governed, what each one can and cannot tell you, and how to keep the answer from going stale.