Samsung Electronics and SK hynix are vying over which is the top stock on the KOSPI. On June 22, SK hynix moved ahead of Samsung Electronics in intraday common-share market capitalisation, seen as a leadership change for the first time in 25 years and 7 months. Samsung Electronics then issued a correction saying it remains No. 1 if preferred shares are included, fuelling a debate over the standard for the "real" top spot.

The Korea Exchange said that as of 12:51 p.m., SK hynix had a market capitalisation of 2,084.6544 trillion won, 456.1 billion won more than Samsung Electronics at 2,084.1983 trillion won. On a common-share basis, it was the first time since November 2000 that Samsung Electronics lost the top spot on the KOSPI by market value. Samsung Electronics first became No. 1 by market value in July 1999 and had not relinquished the position even once from November 2000.

Samsung Electronics moved immediately to rebut. "In some recent articles, preferred shares are omitted and only common shares are reported as if they were the total market capitalisation of the company," it said. "There is a risk of causing investor confusion," it added.

Samsung Electronics argues that market capitalisation is the total value of shares combining common and preferred stock. It said that as of 2 p.m., its market value was 2,252.2 trillion won, adding 183.3 trillion won for preferred shares (820 million shares times 224,750 won) to 2,068.9 trillion won for common shares (5.92 billion shares times 349,500 won). By Yonhap's calculation, the combined market value of Samsung Electronics and Samsung Electronics preferred shares was 2,268.1983 trillion won, about 109 percent of SK hynix's market value.

The rivalry over rankings reflects a gap in share-price gains. SK hynix shares surged 5.82 percent on the day, while Samsung Electronics rose 0.71 percent. So far this year, Samsung Electronics has gained 197.7 percent and SK hynix has risen 341.9 percent.

A fundamental reason is seen as a semiconductor tilt driven by the AI boom. Market participants see SK hynix as having a higher concentration in semiconductors such as high-bandwidth memory (HBM), while Samsung Electronics has a broad portfolio including smartphones, home appliances and displays in addition to semiconductors and is not fully benefiting from the sharp strength in semiconductors.

Expectations for a listing of SK hynix's American depositary receipts (ADR), anticipated for the second half of this year, are also cited as a factor lifting the stock. SK hynix submitted a registration statement for the ADR listing (Form F-1) to the U.S. Securities and Exchange Commission in March. ADRs are securities issued to allow foreign companies' shares to trade on U.S. markets and are a means of widening access for global investors.