A banner at a Woori Bank branch in central Seoul announces the suspension of sales after allocations for so-called national growth fund were exhausted on the first day of subscriptions, Friday. (Yonhap) South Korea's secondary bourse Kosdaq surged nearly 5 percent on Friday, backed by growing expectations over a public investment fund aimed at fostering strategic industries.The junior bourse closed at 1,161.13, advancing 4.99 percent from the previous session.Foreign investors lifted the index, net buying 702.8 billion won ($468.5 million), while institutional investors added 288.1 billion won to the rally. Retail investors were the sole net sellers, offloading a net 969.2 billion won.A buy-side sidecar, which temporarily halts program buy orders to curb volatility, was triggered for a second straight session at 9:33 a.m.Investor sentiment toward the tech-heavy Kosdaq improved sharply after an investment fund offering tax breaks and loss coverage was opened to the public on the day.The fund is expected to channel investments into strategic industries, including in AI, rechargeable batteries, hydrogen and biotechnology, benefiting many Kosdaq-listed stocks.It drew overwhelming investor demand on its debut, with allocations through some distribution channels selling out within 10 minutes of launch.Backed by the anticipation, most large-cap Kosdaq shares rallied sharply.Battery materials makers EcoPro BM and EcoPro jumped 10.77 percent and 12.87 percent, respectively.Jusung Engineering, a first-generation chipmaking equipment company in Korea, surged 20.95 percent.Meanwhile, gains among large-cap biotech shares were relatively modest. Alteogen rose 3.7 percent, while Kolon TissueGene added 3.59 percent.