Samsung Electronics, SK Hynix Now Account for Nearly Half of KOSPI Market Cap as Analysts Split on Further Upside

The artificial intelligence-driven memory semiconductor boom has reached a fever pitch, pushing the combined market capitalization weight of Samsung Electronics and SK Hynix on the KOSPI to nearly 47%. The concentration, with the two stocks accounting for nearly half the market's total value, has hit its highest level in 16 months. However, with share prices soaring, analysts are sharply divided between optimism and caution over further upside.

According to the Korea Exchange on Monday, Samsung Electronics closed at ₩285,500 (approximately $193), up ₩17,000 (approximately $11), or 6.33%. Its market cap was tallied at approximately ₩1,669.11 trillion (approximately $1.1 trillion), representing a 26.04% weight in the KOSPI. SK Hynix surged ₩194,000 (approximately $131), or 11.51%, to close at ₩1.88 million (approximately $1,277). During the session, it hit a fresh record high of ₩1.95 million (approximately $1,324). SK Hynix's market cap was approximately ₩1,339.88 trillion (approximately $910.4 billion), giving it a 20.90% weighting.

The combined market cap weight of the two stocks hit 46.94%, approaching half of the entire KOSPI. This figure had fallen from 26.88% at the end of 2023 to 22.63% at the end of last year, before surging this year as the AI memory boom accelerated. SK Hynix's rally has been particularly pronounced, with annual stock price gains of 22.90% in 2024, 274.35% in 2025, and 188.79% so far in 2026.

Samsung Electronics' first-quarter operating profit jumped 756.1% year-over-year, while SK Hynix's rose 405.5%. Kiwoom Securities forecasts Samsung Electronics' second-quarter operating profit will reach approximately ₩100 trillion (approximately $67.9 billion) and raised its target price to ₩330,000 (approximately $224) from ₩260,000 (approximately $176). Analyst Yoo-ak Park maintained a 'Top Pick' rating for the sector, stating, "Stock momentum remains valid due to factors like rising market share for next-generation HBM4 and eSSD, and improving profitability in the foundry business."

LS Securities raised its target price for SK Hynix to ₩2.1 million (approximately $1,426) from ₩1.5 million (approximately $1,019). Analyst Woo-sung Jung remarked, "The recent stock price surge is less about earnings estimate upgrades and more a result of concentrated fund flows into the leading AI memory stock ahead of key partner earnings reports. The core variables remain HBM sales growth rates and mass production competitiveness."

However, some securities firms have downgraded their ratings due to concerns over short-term volatility from the sharp recent gains. Kiwoom Securities lowered its rating for SK Hynix from 'Buy' to 'Outperform' on Monday. While raising its target price to ₩1.9 million (approximately $1,290) from ₩1.3 million (approximately $883), it views further upside as limited. Last month, on the 27th, BNK Investment & Securities had also downgraded SK Hynix to 'Hold'.

Kiwoom Securities' Yoo-ak Park explained, "The sharp rally in general-purpose memory prices that began last fall is entering its final stages. We adjusted our rating considering the narrowing gap between the target price and the current stock price." BNK Investment & Securities analyst Min-hee Lee added, "Despite steep earnings growth, the semiconductor cycle is entering a late phase. For the second half, one must consider the expansion of lower-margin HBM4's weight and the potential for slowing memory price increases."

On the other hand, Eugene Investment & Securities issued a 'Strong Buy' rating for SK Hynix on the 4th, setting a target price of ₩2.3 million (approximately $1,562). SK Securities offered the most bullish outlook, raising its target to ₩3 million (approximately $2,038). SK Securities analyst Dong-hee Han emphasized, "The recent memory rally is not a simple supply-demand mismatch, but a reassessment of the structural profit-generating power of memory in the AI era. This reassessment is still in its infancy."

While the KOSPI surged over 4% on Monday to break above the 7,820 mark, only 147 stocks advanced compared to 738 decliners. "The semiconductor mega-rally pushed the KOSPI past 7,800 points, but the concentration phenomenon persists," diagnosed Shinhan Investment Corp analyst Jin-hyuk Kang.

Meanwhile, data from Mirae Asset Securities showed that 'super-high-return' investors (the top 1% of traders by returns over the past month) were net buyers of Samsung Electronics and SK Hynix on Monday. The second most net-bought stock was Hyundai Motor. KB Securities analyst Kwi-joon Kim praised Hyundai Motor's growth potential, stating, "By 2035, annual humanoid robot sales could reach 1.5 million units, with Hyundai capturing a 10% market share."