Image: Junk bonds © Tim Bradley, Getty Images

It's kind of Orwellian that anyone would rapaciously buy an exchange-traded fund with the ticker JNK -- branding shorthand for "junk," Wall Street's sobriquet for high-yield, the riskiest layer of corporate bonds.

Nevertheless, the SPDR Barclays Capital High Yield Bond (JNK) ETF and competitor offerings are hot destinations in these yield-famished days. The appeal is irrefutable: You'll get precious little income from Treasurys and municipal bonds. Creditworthy corporations are borrowing at record lows. Why not then pile into riskier, higher-yielding debt, especially if you can do so via one tidy, exchange-traded ticker? (No need to ring Michael Milken.) What's more, Moody's sees the global default rate for "speculative-grade" debt ending the year at 2.8%, compared with an average of 4.8% since 1983. Yields have fallen 1.65 percentage points this year, to 7.05% on Nov. 1, according to Bank of America Merrill Lynch data.

What's not to love?

An overcrowded trade marked by 2007-like issuer complacency, that's what. More companies are demanding and getting easy terms on their junk issues. The most popular junk ETFs are going deeper into credit risk to scrape for yield. The sluicing of retail money into these ETFs is perpetuating what has historically proved to be a vicious trend. "Signs of over-exuberance are creeping into the corporate credit market," wrote Michael Lewitt, a hedge fund manager who publishes the Credit Strategist. "In the past, rising issuance of these types of low-quality bonds has been a warning that a market rally is coming to an end. … Today's new issues will be the troubled credits of tomorrow."

On Nov. 7, Standard & Poor's warned of the unprecedented dangers of a brave new junk bond world. Wrote credit analysts Diane Vazza and Evan Gunter:

"The ease with which investors can enter and exit ETF investments creates new and risky dynamics in the speculative-grade market with the potential flow of 'hot money.' Speculative-grade companies have a higher default risk than investment-grade companies. Therefore, when the credit cycle turns against investors, losses from defaults can quickly outstrip the additional interest payments that high-yield investors receive. Since we are entering the stage of declining credit quality in the current credit cycle, the credit quality of an issuer or a portfolio has become paramount."

Vazza and Gunter looked under the hoods of JNK and its rival, the iShares iBoxx $ High Yield Corporate Bond (HYG) ETF. They found that both funds owned a higher proportion of the riskiest junk debt versus the overall high-yield market. While the analysts estimated that the broad universe of high yield includes 7.9% of bonds rated CCC+ and lower, their share in HYG's portfolio is at 11.0% and in JNK is just under 10%. While higher risk juices returns in a favorable environment like the present one, the analysts explained, they take outsized losses once the credit cycle turns.

Sales of junk debt in the U.S. have come in at $294 billion so far this year, the fastest pace on record. It's in that booming backdrop that private-equity-owned companies have paid out $34.1 billion in dividends this year, according to Standard & Poor's Capital IQ Leveraged Commentary & Data. That's north of 2010's total of $31.5 billion and the $23.8 billion paid out in 2007, when the leveraged buyout market peaked. For comparison, $1.2 billion in dividends were issued in 2008 and $440 million in 2009.

This boom has prompted an echo-boom in payment-in-kind transactions, or PIK toggles, which let companies pay interest in debt rather than cash, essentially deferring payments to their investors. That tactic was a hallmark of the private equity bubble of five years ago. According to Moody's, as of mid-October two of the third quarter's 14 dividend financings enjoyed PIK toggle structures, including Emergency Medical Services' $450 million of notes to pay a dividend to Clayton, Dubilier & Rice and IDQ's $45 million deal supporting a payout to Castle Harlan. Last month, Petco also got in on the PIK toggle boom.

Caveat junktor: Moody's calculates that the default rate for companies that sold PIK-toggle bonds was 13% from 2006 to 2010, twice the rate for similarly rated issuers that didn't use the tactic.

"Low yields are driving more and more investors into really strange territory," says Lee Pacchia, a Bloomberg Law analyst who follows corporate bankruptcies. "They need to take on risk. While the market forces driving this trend could go on for a while, lowering standards could end badly. It's called 'junk' for a reason."

The institutional smart money is increasingly taking the other side of that trade. According to Bloomberg data, bearish options on HYG are at an all-time high: The number of outstanding puts on HYG has almost doubled since Oct. 19, to a record of 118,444 at the end of last month. Hedge funds seeking that bet on both gains and losses in credit attracted $12.6 billion of deposits in the three months ended Sept. 30, the most since the last quarter of 2007, according to HFR.

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It all makes you wonder how quickly people may have forgotten the lessons of the credit bubble, or what one hedgie has called the era of promiscuous lending. Will today's junk boom end so differently?

"The history of money is a sad state of affairs," wrote Prudent Bear's Doug Noland in his recent post, titled "The Myth of Deleveraging." "Failing to learn from a litany of previous monetary fiascoes, 'money' is these days being abusively over-issued."

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