Marex Group plc, the London-born brokerage now listed on Nasdaq under the ticker MRX, has posted another quarter of sharp growth despite a lull in global derivatives trading.The company said in a preliminary update that third-quarter revenue will come in between $475 million and$485 million, up 23% year on year at the midpoint, with adjusted profit before tax climbing 22% to as much as $101 million. Its adjusted return on equity hovers around 27%, and profit margin near 21%.That momentum came even as futur ...