Is foreign exchange intervention effective? Some microanalytical evidence from the Czech Republic

I estimate a two-equation system on the Czech koruna-euro exchange rate and order flow at hourly frequency with transactions data from the Reuters Spot Matching market in the second half of 2002, during which the Czech National Bank intervened to stem the appreciation of the koruna. I find a significant impact of order flow on the exchange rate, equal to 7.6 basis points per €10 million, of which 80% persists throughout the day. The news of intervention increases the price impact of order flow by 3.9 basis points per €10 million. The order flow equation yields inconclusive results.