A federal jury found former Goldman Sachs Group Inc. trader Fabrice Tourre liable for defrauding investors in a deal that imploded during the financial crisis, delivering a victory for a U.S. regulator out to prove its mettle inside the courtroom.

The panel of nine jurors found Mr. Tourre liable on six of seven claims that he violated federal securities law by intentionally misleading investors. The jurors also determined he had aided and abetted an alleged fraud by Goldman.

...