John Olson, a senior securities partner at Gibson, Dunn & Crutcher, says he knows which two cases are about to become the talk of the securities bar.

One, the U.S. Securities and Exchange Commis­sion’s action against billionaire Mark Cuban, has already generated a lot of hype. But the other one — a suit that has so far kept a low profile — could be even more significant. It’s the case brought by the SEC last month accusing a Deutsche Bank Securities bond salesman and a former Millennium Partners hedge fund manager of insider trading in credit default swaps — the derivatives blamed for much of the economic meltdown.