South Korean secondary battery stocks showed renewed strength on the 31st, outperforming a KOSPI that fell 2% at the market open. L&F rose 4.6% to 143,400 Korean won during morning trading, while POSCO Future M gained 3.44% to 192,700 won. Samsung SDI and LG Energy Solution advanced 1.93% and 1.08%, respectively, although POSCO Holdings and EcoPro declined 0.3% and 0.44%. The rebound has been supported by recovering lithium prices, expectations for an expanding U.S. ESS (energy storage system) market, and efforts to shift supply chains away from China. Shares had weakened after leading the domestic market in the first half of 2023 and entering a correction in July, but major battery stocks have posted double-digit gains this month, marking their first significant rebound opportunity in three years. From the start of the month through the 28th, L&F and EcoPro each rose 85%, Samsung SDI gained 47%, POSCO Future M advanced 36%, LG Energy Solution climbed 17%, and POSCO Holdings increased 11%. Growing electricity demand from AI data centers has strengthened expectations that ESS will become a new growth engine as electric vehicle demand slows. Investors also see potential for buying interest to broaden beyond semiconductor stocks, while expectations are building for large-scale investment by Samsung SDI after it announced plans to sell 4.45 trillion Korean won worth of Samsung Display shares to fund future growth initiatives. Secondary battery ETFs (exchange-traded funds) also ranked among the strongest domestic listed funds, led by leveraged and materials-focused products. Despite the rally, major stocks remain well below their peaks, leaving many retail investors who bought during the secondary battery boom unable to recover their principal. Kyobo Securities research analyst Choi Bo-young said the move reflects more than cyclical buying, citing policy support centered on ESS. She said South Korean companies with production capacity in North America could gain relative value as the U.S. treats ESS as core national security and grid infrastructure equipment. Future performance, she said, will depend on order volumes, utilization rates, and quarterly earnings improvements.