Investor optimism about the pill version of weight-loss injectables being developed by Sam Chun Dang Pharm (SCD) in South Korea has fueled a rally in its shares, which are up by more than 75% so far this month. The stock surge has propelled Yoon Dae-in, the company’s chairman, into the billionaire ranks.
Yoon, who turns 76 in March, directly and indirectly owns 34% of the company’s shares. He also has a small stake in OPTUS Pharmaceutical, the eye-drop manufacturing arm of SCD. Forbes estimates Yoon’s net worth at $2.1 billion.
Based in Hyangnam, south of Seoul, SCD develops active pharmaceutical ingredients used in treatments for dry-eye disease and high blood pressure. The company also develops novel drug delivery systems, such as S-Pass, which turns injectable medicines into easy-to-take pills.
On Thursday, SCD announced that it had signed an agreement with Japanese drug maker Daiichi Sankyo to jointly develop and commercialize SCD’s weight-loss pill, which was developed using S-Pass, in Japan. While the financial terms of the deal have not yet been finalized, SCD shares are up almost 40% since the announcement. Last week, Seoul-based investment bank Korea Investment & Securities selected SCD as a “recommended stock of the week” citing S-Pass’s “potential for clinical success as a formulation technology for oral obesity and diabetes treatments.”
Another novel drug delivery system developed by SCD is the microsphere-based long-acting injectable, which injects timed-release micro-pellets to release the drug slowly over several months. On January 7, SCD announced it signed a deal potentially worth up to $2 billion for the exclusive right to sell a long-acting injectable version of leuprorelin, a hormone medication developed by Japan’s Takeda that is used to treat prostate cancer, in the U.S. SCD developed the long-acting injectable version, which uses the microsphere technology, for which it will receive about $100 million upfront and in milestone payments, with the rest of the $2 billion coming from a 50-50 profit sharing.
SCD’s revenue rose 6.3% year-over-year to 165.5 billion won ($113 million) in the first nine months of 2025, while net income increased 76% from the year-ago period to 70 billion won in the same period.
SCD was established in 1943 during the Japanese occupation (1910-45) under the name Chosun Sam Chun Dang. (There is no public information about its founder.) In 1986, after completing his M.B.A. studies from Long Island University in New York, Yoon, whose father owned medical centers and educational institutions, used family funds to acquire Chosun Sam Chun Dang for an undisclosed amount. SCD listed on Korea’s technology-rich Kosdaq stock exchange in 2000, raising 9.1 billion won in its IPO.
Yoon, who did his undergraduate studies in business at Seoul National University, was co-CEO of SCD with his son-in-law Chun In-seok until 2022. Chun, who joined the company in 2014, remains CEO.
Yoon joins a galaxy of South Korean biotech and pharma billionaires, including Seo Jung-jin ($8.5 billion) of biosimilars giant Celltrion; Park Soon-jae ($2.7 billion) of Alteogen; Chung Yong-ji ($2.1 billion) of anti-wrinkle shot-maker Caregen; Lee Sang-hoon ($1.6 billion) of ABL Bio; Jung Sang-soo ($1.2 billion) of PharmaResearch, which makes skin booster injections derived from salmon sperm cells; and Hyuntae Kim ($1 billion) of Voronoi, which develops cancer drugs using AI.
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