Upbit's JPYC: 21,219 Korean Investors Bought the Yen Stablecoin Above Peg

JPYC Trades Far Above Its Peg on Upbit

More than 21,000 South Korean investors paid over the reference price for JPYC, Japan's yen-pegged stablecoin, in the days after the token listed on Upbit, the country's largest crypto exchange. Figures compiled by South Korea's Yonhap News Agency show 21,219 investors bought JPYC at prices at least 10% above its one-yen reference level, for a combined 259.86 billion won — roughly 28 billion yen — between the Sept. 17 listing and Sept. 21. The episode amounts to the first serious stress test for a fiat-pegged token on a top-tier venue: unlike a speculative altcoin listing, the divergence exposed an arbitrage gap between the issuer's redemption service and the token actually available on the open market.

The mechanics explain the spike. JPYC is built to be issued and redeemed one-to-one with the Japanese yen, so in principle a token should always be worth one yen. On Upbit, however, the quantity available to trade was limited at launch while buy orders poured in, pushing the market price far past the peg — it surged toward roughly double the reference level and stayed elevated for days. The same breakdown shows 11,449 investors bought at three to four times the reference price, spending 85.42 billion won (about 9.2 billion yen), while 13,728 bought in the two-to-three-times band for 105.86 billion won (roughly 11.4 billion yen). Another 2,574 paid four times the peg or more. As of Sept. 21, 3,792 investors who had bought high and still held faced average unrealized losses of about 1.33 million won (roughly 140,000 yen) apiece — about 5.03 billion won in aggregate. Some 7,006 buyers, 33% of the high-price cohort, had already exited with gains, averaging 453,687 won (about 49,000 yen) in realized profit each.

Japan Arrests Two in ¥81 Million Crypto Scam

The arrests landed on the enforcement side of the same market. Japanese police detained Saki Okayama, 31, and Mitsuki Minamisawa, 38, over a scheme that allegedly stole about 81 million yen — roughly $515,000 — in cryptocurrency from a woman in her 40s, a case detailed in reporting by Japan's FNN on Sept. 25. Investigators say callers impersonating the Osaka Prefectural Police told the victim her bank card had surfaced in a money-laundering probe supposedly involving 600 billion yen in losses and around 400 accounts, and that she had to “prove her innocence” by moving assets. The group is believed to have run its operation from Cambodia, more than 4,000 kilometers from Japan, with a Chinese national suspected of directing it; confirmed losses in cases linked to the two suspects total roughly 240 million yen. Neither the specific cryptocurrencies involved nor the receiving wallet addresses have been disclosed, so the on-chain trail remains unestablished. News of the case spread quickly after being summarized on X.

The case lands amid a surge in impersonation fraud. Japan's National Police Agency logged 61.71 billion yen in fake-police scam losses across 5,422 cases through July — case counts down 6.4% year over year, yet losses up 25.7% — within total special-fraud losses of 210.81 billion yen, up 42.9%. A separate Sept. 25 case cost a man in his 70s about 73 million yen. In August, the Financial Services Agency and the National Police Agency asked exchanges — a group spanning many of the best crypto exchanges serving Japanese users — to weigh withdrawal delays and tougher checks on newly registered wallet addresses. Regionally the pattern is familiar: South Korean police arrested 23 people in June over an alleged USDT laundering operation serving a Cambodia-based phishing network, where flows historically settle in dollar tokens on networks such as TRON — the same friction Tether's dedicated Stablechain network is being built to remove. Readers tracking the market in real time can follow live spot and futures prices on MEXC.

COINOTAG's reading: one week delivered both faces of Japan's crypto build-out. The primary record here — the National Police Agency's own statistics — shows fake-police fraud cost 61.71 billion yen through July, with losses rising 25.7% even as case counts fell 6.4%, meaning each successful strike is getting larger. At the same time, JPYC's Upbit debut proved there is genuine retail demand for yen-denominated digital money, and its doubled market price proved the arbitrage plumbing is not ready. Whether Japan's market matures into a real yen-stablecoin rail or hardens into a fraud surface will hinge on the August-requested controls — withdrawal delays, wallet screening — arriving before the next 81-million-yen case, not after it.