Business leaders and financial markets will be watching closely early Thursday morning when the Commerce Department releases figures on the nation's export and import performance in October. Widening of the trade deficit normally drives down the markets, which already are depressed.

September's figures showed some improvement, with the deficit dropping to $14.1 billion, the best in four months; the Dow Jones industrial average responded with a 61-point rise. Worse-than-expected results for August had helped set the stage for the 508-point free fall of Black Monday.

On Friday, Commerce will make another closely analyzed disclosure, that of figures for the nation's retail trade in November. One of the big unanswered questions in the wake of the stock market collapse is whether it will scare people out of major retail purchases, thereby helping to bring on a recession. Friday's figures could help answer that.

But even in the business community, those events may be overshadowed by the week's big news in Washington and the rest of the world: the face-to-face meeting here between President Reagan and Soviet leader Mikhail Gorbachev. In fact, U.S. corporate leaders are reportedly scheduled to call on the Soviet visitor at the Soviet Embassy while he's in town.