A couple weeks ago I asked a question - How is this not a bubble? - after reading this.

Interest rates today are the lowest they’ve been at least since Stonehenge was under construction and the pharaohs of the First Dynasty ruled Egypt, Bank of America Merrill Lynch (BAML) said in a report this week.
In fact, according to another new report, this one from the Bank of Montreal, interest rates have fallen so far that some governments can actually make money by borrowing it — essentially destroying any argument for spending cuts.

Then today I ran across this article on the ultra-bullish Yahoo financial site.

"We're in an epic bubble of colossal proportions," Peter Boockvar, managing director and chief market analyst at The Lindsey Group, said Tuesday on CNBC 's " Futures Now " in reference to the fixed income market....
Ultimately, Boockvar warned of the fallout that could occur if multiple nations opt to end what he referred to as a "negative deposit rate regime."
"Even if they put it back to zero, imagine the carnage, at least in the short-term bond markets," concluded Boockvar.

OK. It's one person's opinion. It doesn't mean much more than that, amirite?
Actually, no.
How can I be so certain? Because of this.

The downward march of long-term bond yields in 2016, which have sent the entire Swiss yield curve into negative territory, has been a wonder to behold.
For investors who bet on super-low yields to go even lower this year, the returns in the first half of the year have been stunning...
The standout performer, the Japanese long-term bond, has rallied by more than 30 percent year-to-date.
By contrast, an investment in the S&P 500 at the start of 2016 would have garnered a total return of roughly 4 percent at the end of the first half.

To sum this up:
one of the best performing investments you could have made this year is to PAY SOMEONE TO BORROW MONEY FROM YOU.

Wait..What?

Let me put this another way.
Bond prices and interest rates are directly inversely correlated. So the lower interest rates go, the higher the price of the bond. It still applies when interest rates go negative.
So current bond holders will celebrate at negative rates (NIRP)...However, negative rates will gradually eat into those profits of recent buyers. Therefore rates have to go more negative at a faster rate to make up the difference, which of course, eat into those profits even more.

Does that somewhat Ponzi-ish?
The Ponzi in this case are the central banks, and like any good Ponzi scheme, someone has to loose money.

Let me correct that: investors aren’t buying the JGBs anyway. The only entity that is buying on a net basis is the BOJ. Everyone else is selling. And when these investors slow down their selling just one notch, even as the BOJ continues mopping up every JGB that isn’t nailed down, yields fall further.
What does this mean for investors that bought bonds with long maturities years ago? For example the German 4.75% Bund, issued in 2008 and due in July 2040 trades at 202.3 cents on the euro, having doubled its value over the past eight years. The sellers of those bonds are the true beneficiaries of Draghi’s monetary policies, and they can sell them right to the ECB.
But long-term investors, like insurance companies and pension funds, hold bonds to maturity to create predictable income streams to pay for predictable benefits decades down the road. They’re going to get face value for these bonds when they’re redeemed. And 30-year bonds that these insurance companies and pension funds are now buying have a yield of 0.32%. Next to nothing!
They’re completely screwed. Or rather, the regular folks who are supposed to get these payouts in the future are completely screwed.

Well, just wait, because you haven't seen the craziest part yet.

The price of junk-rated Ohio tobacco debt that may never be paid in full has climbed 14 percent since the start of the year. New York City’s Albert Einstein College of Medicine sold $175 million of unrated securities in January at par for a yield of 5.5 percent. Now, they’re worth 122 cents on the dollar and yield 2.8 percent, according to data compiled by Bloomberg. Even those issued by Puerto Rico, which has been defaulting on a growing share of its debt, have returned 8.4 percent.

The same Puerto Rico that just defaulted on $2 Billion in debt.
The same Puerto Rico that just got it's credit rating cut by Fitch to 'D'.
Note that a rating of 'D' is BELOW junk.
If you loaned money to this dead-beat, your return on investment would have been DOUBLE the stock market this year.

Wait a sec. Making money by loaning money to broke dead-beats.
Where have I heard this before? I seem to remember something about this from a decade ago.

Everyone seems to be ignoring that fact that ultra-low interest rates and flat yield curves have almost always been the sign of an economy in real trouble.

The spread between the yield on 10-year and two-year U.S. Treasury notes narrowed in the immediate aftermath of the June 23rd referendum, widened briefly, and is now shrinking again as investors continue to flock to the perceived safety of U.S. government debt. A model maintained by Deutsche Bank AG's Steven Zeng, who adjusts the spread for historically low short-term interest rates, suggests the yield curve is now signaling a 60 percent chance of a U.S. recession in the next 12 months — up from a 55 percent probability as of mid-June, and the highest implied odds since August 2008.
"This relentless flattening of the curve is worrisome," Deutsche analysts led by Dominic Konstam said in their note on the model. "Given the historical tendency of a very flat or inverted yield curve to precede a U.S. recession, the odds of the next economic downturn are rising."

If you need help understanding this, and I don't blame you if you do, watch this video below.