Motivated by the argument that central bank intervention leads to non‐linear exchange rate adjustment processes, we examine purchase power parity (PPP) by applying quantile unit root tests to the exchange rates of the New Taiwan Dollar (NTD) vis‐à‐vis seven Asian currencies. We show that exchange rate regime matters in determining whether PPP holds. While PPP holds overwhelmingly during the period when the NTD is under the fixed exchange rate regime, it is present only for some exchange rates during the managed floating rate regime. For exchange rates exhibiting mean reversion, the reversion occurs mainly when the shocks are large. In contrast to conclusion in the literature, our test results show little evidence of asymmetric mean reversion between positive and negative shocks.