The U.S. Treasury’s Series I savings bonds are no longer a forgotten investment option.

In fact, the government-guaranteed, inflation-protected securities are now among the hottest assets around. The Treasury disclosed that it issued $1.312 billion of Series I bonds in November, according to data released late yesterday. That’s by far the most on record since the department began breaking out monthly totals eight years ago. Considering that individuals are limited to buying $10,000 a year, that suggests at least 131,200 people sought out the debt, on top of the hundreds of thousands of Americans who had already made their yearly purchase earlier in 2021. (Treasury also allows individuals to purchase up to $5,000 a year of paper Series I bonds specifically by using their federal tax refund on top of the $10,000 annual maximum.)

The reason for the sudden rush of demand is straightforward: The interest rate on Series I bonds, which resets twice a year, soared to 7.12% as of Nov. 1 and is good through the end of April. That’s double the 3.54% composite rate offered from May through October and is even higher than the 6.2% consumer price index reading for October that forced the Federal Reserve to abruptly signal tighter monetary policy ahead to constrain price growth. The variable rate rises and falls depending on headline CPI specifically, making it a consistent hedge to persistent inflation pressure.

I referred to Series I bonds as an “anti-Bitcoin asset” in May, just before monthly issuance reached the second-highest level ever. And while that description is still largely applicable, especially after witnessing the crypto crash over the weekend, there’s one way in which they’ve become similar: Hype.

It’s hard to imagine a more captivating headline than this one from Bloomberg News’s Emily Cadman on Nov. 1: “Earn 7.12% Risk-Free on Your Savings, No Crypto or Junk Bonds Needed.” Here’s CNBC and Yahoo Finance the following day: “Sweating inflation? This risk-free bond pays 7.12% annual interest for the next six months” and “The little-known type of bond that’s paying 7.12% in interest right now.” All told, the sudden rush to tout the Series I bonds sent Google search interest skyrocketing. Judging by the big November issuance figure, more people than can fit in the University of Michigan’s supersized football stadium were convinced enough to set up a TreasuryDirect account (which is somewhat archaic) and lock their money away for a minimum of a year.

Of course, with the Fed signaling it will wind down its asset purchases sooner than expected, this could be about as good as it gets for Series I interest rates. The bonds do have a fixed-rate component, which is currently pinned at 0%, but even when the fed funds rate was raised above 2% in late 2018, the fixed rate on the Series I securities was just 0.5%. The debt is a pure inflation play.

Still, it’s not as if fixed-income markets offer better alternatives. The yield on Bloomberg’s U.S. high-yield corporate bond index is just 4.68% after falling to as low as 4.03% last month. Meanwhile, rates on Treasury Inflation Protected Securities are deeply negative even out to 30 years, underscoring the mismatch between inflation and U.S. yields. Plus, Series I bonds have the benefit of interest that’s exempt from state taxes and can be excluded from federal income taxes if used to fund education. Top-rated 10-year municipal debt, which offers similar advantages, yields just about 1%.

The secret is out on Series I bonds. After several days of elevated volatility in stocks and crypto, and just weeks before the end of the year, the only question is whether the merits of these savings bonds have reached their full audience or whether there are still hordes of investors who are worried about inflation and who would benefit from picking some up during the holiday season.

Brian Chappatta is a Bloomberg Opinion columnist covering debt markets. He previously covered bonds for Bloomberg News. He is also a CFA charterholder.