The Five Dumbest Things on Wall Street This Week: April 4

5. UBS -- Stands for 'Under the Bus'?

UBS UBS managed to make April Fools out of U.S. investors Tuesday.

The Swiss bank rode a wave of second-quarter spring fever for financial stocks even as it showered the market with bearish news.

The company announced it faces $19 billion in writedowns tied to ever-proliferating subprime exposure, which has jumped across the formidable barriers of the Atlantic Ocean and the Alps to infect the brokerage. To address its problems, UBS announced that it would seek $15.1 billion in financing and that Chairman Marcel Ospel would be leaving the company.

Ospel took credit for the bank's hefty exposure to bad debt as he abdicated his chair. "We have worked very hard and have been able to address the firm's most pressing problems, thereby laying the foundation for the long-term success of the bank," he said.

And now, Ospel seemed to say, someone else can clean up the mess.

Fellow UBS honcho -- and fellow Marcel -- CEO Marcel Rohner, will be left with much of that task. "The write-downs are very large and unprecedented, they are also necessary for us to turn the page," he said on an analyst conference call.

Investors seemed cheered by the wisdom of their new Marcel, buying UBS as though the company's April 1 share offering were an elaborate prank, perhaps a buyback in disguise.

Dumb-o-meter score: 65. "My willingness to stand for re-election for a further one-year term was based on my desire to lead UBS out of its current difficult situation," Ospel said. Well done, Marcel. We were almost fooled.