(Bloomberg) -- China’s state media urged investors to refrain from engaging in speculative trades in the latest special sovereign bond, as an illiquid part of the market saw a retail buying scramble Wednesday.

The Shanghai and Shenzhen exchanges had to halt trading in the security Wednesday on the bond’s debut as retail investors drove it as much as 25% higher. The 30-year security was just issued on Friday and its price was little changed in the separate interbank market where most bond trading takes place, largely between institutions.

“Some retail investors could be irrationally chasing a rally and the buying frenzy may end up in losses should supplies of such bonds increase,” the Securities Times reported. Investors should be cautious of the huge price swings in low trading volumes, China Securities Journal said in a report.

The special bonds are part of government efforts to revive an economy afflicted with a property downturn and poor business confidence — and to ensure an ambitious annual growth target of about 5% is met. Friday’s 40 billion yuan ($5.5 billion) sale was the first batch of an approved quota 1 trillion yuan this year.

Demand for debt has boomed among Chinese investors this year as the nation’s economic woes deepened risk aversion and fueled demand for safer assets. Retail investors have traditionally turned to bank deposits, wealth management products and the stock market for returns, rather than directly buy bonds.

The highest price for the 30-year bond on the exchange Wednesday implied a hold-to-maturity yield of 1.53%, significantly lower than the 2.56% seen in the interbank market. That level was even below rates seen in traditonal low-yielding regions, including Taiwan and Japan.

It’s not the first time the exchange market saw wild bond prices as yields turned negative in 2021 on debt sold by China Development Bank. There have also been several trading halts on regular government bonds on the Shanghai bourse in the past month.

“China’s exchange market is not a mainstream venue of bond trading and individual investors may lack knowledge on how to price bonds,” Huaxi Securities analysts including Liu Yu wrote in a note. The price swings in the special bonds may be a result of some investors trading it like stocks, they wrote.

The finance ministry will issue 40 billion yuan of 20-year notes on Friday, its second offering of special bonds this year. Earlier this month, China released a plan to sell 1 trillion yuan of ultra-long special debt over a time span of about six months through November.

(Updates with Friday’s bond auction plan)

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