Designing DTOs as inner classes

Is it ok to design DTOs/parameter wrapper objects as inner classes? Is it common practice or does it have any major drawbacks? E.g:

//I want to initiate threads with parameters
public class TradeBot implements Callable<TradingReport> {

//I have a few parameters, so I decided to wrap those into an object
TradeBotParamDTO params;

//the wrapper for parameters is actually an inner class:
public class TradeBotParamDTO {
    JsonNode config;
    Instrument instrument;
    TimeframeBarMQL tf;
    int numberOfBars;
    int port;
    String host;

}

//Constructor to instantiate the Runnable with parameters
public TradeBot(TradeBotParamDTO params) {
    super();
    this.params = params;
}


@Override
public TradingReport call() {
//access params here...
params.getXXX()
... 
}
}