Paul Krugman points out that word from Fitch that a U.S. downgrade is now unlikely because of the debt ceiling has been temporarily suspended seems to have contributed to this morning's Treasury retreat.

"That's right, reduced fears of a downgrade lead to higher, not lower, US borrowing costs," Krugman writes.

Aleksey Vayner has died.

Vayner's death was first reported by the website IvyGate, and later confirmed by a relative who spoke to Gawker.com. New York Daily News also confirmed the story.

"It looks like he took some drugs or medicine, had a heart attack, a friend of his drove him to the hospital, and they couldn't resuscitate him," a person Gawker identifies as a cousin-in-law said over the phone this afternoon. "Not exactly sure though."

The New York City Medical Examiner public affairs office confirmed to several media outlets that a 29-year-old man named Alexander Stone died in Jamaica Hospital in Queens, NY Saturday. Apparently, Stone was Vayner.

Call them the "Bickering Billionaires," two financial titans who squared off in a breathtaking, unforgettable smackdown Friday on CNBC.

Bill Ackman, the head of Pershing Square Capital Management and its $12 billion in assets, squared off against Carl Icahn, the fellow activist investor and one of the richest men in America with an estimated fortune of nearly $15 billion.

The debate revolved around charges and countercharges, with Icahn calling Ackman dishonest and "a major loser," while Ackman countered that Icahn is a bully "not used to someone standing up to him."

Traders at the New York Stock Exchange punctuated the air with "oohs" and "aahs" during the arguing, while social networks lit up, with financial journalists and market watchers tweeting and posting as fast as their fingers could type. (Read More: Ackman: Icahn Wanted to Be My Friend, I Said No)

The setting was during the final half-hour of CNBC's "Fast Money Halftime Report" with Scott Wapner, who found himself as much of the story as the two participants.

Icahn repeatedly berated Wapner. Icahn insisted he was the one being bullied and on several occasions used the word "bullsh--" to describe his feelings about the on-air forum.

Apple's tumble back down from the stratosphere did some damage to the stock's other-worldly reputation but helped out some of its peers in the process.

Short-term market participants have been using the tech titan's shares in what are known as pair trades - betting that one stock will go higher while hedging that bet by short-selling a stock expected to go lower.

It's a strategy that has worked particularly well over the past five months as Apple's stock has crumbled while the rest of the market has surged higher. Anecdotal evidence from traders indicates that it's essentially an unraveling of the opposite trade that had been taking place prior to Apple's fall.

In what may have been the most epic smackdown of rich guys to ever play out in public, Bill Ackman and Carl Icahn confronted each other on CNBC's "Fast Money Halftime Report" over dealings going back to 2003. (Read More: Ackman, Icahn Hurl Accusations, Insults.)

A panel at the Davos conference has apparently convinced Felix Salmon that self-driving cars are the future. He even thinks these may even be better than rail, which has been high on every planner's list of ways to improve the world.

So what makes self-driving cars so terrific?

Billionaire activist investors and longtime rivals Carl Icahn and Bill Ackman are at it again.

This time, the two are tangling over Ackman's short position in Herbalife, a debate that extended itself into barbs over a 10-year-old legal dispute.

In a televised appearance Thursday, Icahn ripped Ackman for publicly revealing a large bet against Herbalife late last year. Icahn reportedly has taken a long position in the company.

(Read More: Billionaire Carl Icahn Takes Herbalife Stake: Reports)

In a CNBC interview last month, Ackman labeled the company, which sells weight-loss and nutrition products, a pyramid scheme. He said he had borrowed more than 20 million shares to sell, later hoping to buy them back at a lower price and pocket the difference, a process known as short-selling.

The public nature of the move was "disengenous," Icahn said in a Bloomberg television interview Thursday in which he said he neither liked nor respected Ackman.

Jesse Eisinger paints a pretty awful picture of banker misbehavior in his latest Pro Publica column.

On March 16, 2007, Morgan Stanley employees working on one of the toxic assets that helped blow up the world economy discussed what to name it. Among the team members' suggestions: "Subprime Meltdown," "Hitman," "Nuclear Holocaust," "Mike Tyson's Punchout," and the simple-yet-direct: "Shitbag."

These facts have come to light thanks to a lawsuit brought against Morgan Stanley by a Taiwanese bank that invested in a $500 million collateralized debt obligation. According to Eisinger, $415 million of the assets backing the CDO, which was actually called Stack 2006-1, wound up being worthless.

Most of those suggested names came from a lawyer at Morgan Stanley named Phillip Blumberg. His emails were released to the public as part of the lawsuit. It's just incredible that this sort of thing still gets sent around in emails just a few years after Wall Street's equity analysts found themselves under fire for, among other things, sending internal emails dissing the stocks their firm's were selling to the public. They'll never learn, I guess.

Despite a fairly dramatic recent decline in weekly unemployment claims, the notion of a significantly improving job market is drawing few converts.

The Labor Department dropped another surprise Thursday on Wall Street with news that the total of new jobless claims fell by 5,000 to 330,000, a release that came against expectations that last week's tumble to 335,000 was a statistical blip.

Not only was this week's total well below economist estimates of 360,000, but there also was no revision from the previous number. The government routinely fiddles with its data as more information flows in. (Read More: Weekly Jobless Claims Keep Up Steady Move Lower)

Still, the Street remained tepid at best and disbelievers at worst.

"We are cautious not to read too much into the recent sharp drop in claims as the data have in the past been distorted around the beginning of the year," said Joe LaVorgna, chief US economist at Deutsche Bank. "However, the fact that the four-week moving average has been steadily declining over the past three weeks could be a signal that the labor market is poised to up shift."

"This is mostly noise not a signal. The move last week and this week are biased on the low side due to seasonal factors," Stephen Staley, chief economist at Pierpoint Securities, said in a more pointed analysis. "They will likely pop back up."