In-vitro diagnostic medical device companies, whose stock prices soared amid expectations for growth during the COVID-19 pandemic, are struggling to escape from a recent slump.

Top diagnostic companies, including Seegene, SD Biosensor, and Humasis, have also seen their share prices drop sharply.

Seegene, the market bellwether among in-vitro diagnostic companies, closed at 26,800 won ($19) on the last day of September, a 12 percent slide compared to the beginning of the month. When compared to November of last year, when the company's stock price rose to 83,900 won due to the start of the Omicron pandemic, the share price of the company has fallen by 68 percent.

Seegene is one of the biggest beneficiaries of the Covid-19 pandemic. Seegene's stock price jumped from 15,000 won at the end of 2019 before the Covid-19 spread to 161,926 won in Aug. 2020.

The situation is the same for SD Biosensor.

SD Biosensor was listed at an initial offering price of 52,000 won in July last year, but the current share price has fallen to 26,600 won.

SD Biosensor's stock price had soared to 81,000 won in early February when the number of confirmed COVID-19 cases skyrocketed, but since then, it has been on a downward trend and has plummeted by about 67 percent from its previous high.

The market cap also fell sharply. While SD Biosensor market cap reached 6 trillion won at the end of March, it has now fallen to 2.7 trillion won.

Humasis also recorded a 52-week new high of 36,450 won in February. However, Humasis' share price also turned downward and faced conflict with some minority shareholders due to the sluggish stock price.

As stock prices continue to fall, companies are preparing measures such as buying back shares to enhance shareholder value.

Seegene decided to buyback 50 billion won worth of shares on Sept. 28, which it plans to complete within six months.

With the recent buyback, Seegene has repurchased 130 billion won worth of shares over the past two years.

The company also plans to review various ways to enhance shareholder value by using dividends according to market conditions.

Humasis also announced that it had signed a contract to buyback 20 billion won worth of shares last Friday, with the aim of stabilizing stock prices and enhancing shareholder value.

Humasis had also signed trust contracts to repurchase 10 billion and 20 billion won in March and May, respectively. In September, the company continued its shareholder-friendly policy, including retiring 5 billion won worth of its shares.

"The reason the recent drop in the stock price of diagnostic kit makers is due to countries adopting an endemic stance toward the Covid-19 pandemic," said Lee Jun-soo, an analyst for Prophet Asset Management. "This has led to investors fearing that the performance of Korean diagnostic companies will return to pre-Covid-19 level.

This trend is growing as the Korean government is also changing its Covid-19 quarantine policy, such as removing face masks outdoors and removing the Covid-19 polymerase chain reaction (PCR) testing requirement for inbound travelers, Lee added.