Mark Zaino, a former UBS trader who worked on the firm’s derivatives and municipal securities desk, pleaded guilty to fraud and conspiracy charges today in the wide-ranging investigation into sham auctions and bid rigging in financial products sold to municipalities.

Senator Carl “Shitty Deal” Levin has blasted the Swiss government withholding the names of withholding the names of certain UBS clients suspected of opening Swiss bank accounts to evade U.S. taxes. The Swiss lower house voted today to reject a U.S.-Swiss treaty that would have turned over about 4.450 out of the 52,000 UBS clients the Uncle Sam suspects of tax evasion.

Roomy Khan, one of the key cooperating witnesses in the Galleon insider trading case, used her extensive rolodex of insiders to gain access to secret market-moving information. Recently released court documents show that list of contacts could be longer than we thought.

If you thought the SEC’s charges against Goldman Sachs poured fuel on an already-raging populace fire, Wall Street’s involvement in a massive bid rigging scandal in the $2.8 trillion municipal bond market will fan the flames even more.

Say “auf Wiedersehen” to naked short selling in Germany. Because of “exceptional volatility” in euro-area government bonds and credit-default swaps, massive short-selling was leading to excessive price movements which “could endanger the stability of the entire financial system,” Germany’s BaFin financial services regulator said today.