A, who works at a platform corporations, recently put a privacy screen protector on a smartphone. It was to check the mobile trading system (MTS) at the office without worrying about people nearby. A said, "It was recommended as a 'pro tip' for office worker investing," and added, "I can't open stock windows on the company PC due to security issues, but it's useful because I can conveniently check prices at my desk and make trading decisions."
Some office workers go so far as to choose smartphones with built-in privacy display features. A 40-something employee at a large corporations recently switched to a Galaxy S26 and cited the screen protection feature as one of the reasons.
As Korea's stock market has swung sharply in recent days, more office workers are checking MTS during work hours. With volatility rising and more retail investors engaging in short-term trading, a culture is spreading where people can't stop checking prices on the job. On the other hand, some note that excessive stock trading hurts concentration at work and burdens colleagues.
◇"When a stock alert sounds, it's off to the restroom"… office workers' "scalping war"
On the 18th, the business community said many business sites see office workers checking MTS in restrooms or emergency stairwells around 9 a.m., when regular trading opens on the domestic market. At their desks, they often worry about others' eyes or face restrictions on work PCs, so they briefly step away to check prices.
A 30-something office worker surnamed Lee also logs into MTS for about 10–15 minutes from 9 a.m. on weekdays to check the market's flow and the moves of holdings. Lee said, "When a price alert sounds during work, I go to the restroom or emergency stairwell, check prices, and then decide whether to trade," adding, "These days, at lunchtime, Samsung Electronics or SK hynix share prices are a regular topic among employees."
One reason office workers can't easily close their trading windows during work is the high volatility in Korea's market. That day, a sell-side sidecar was triggered on the KOSPI market. A sidecar is a mechanism that halts program trading for five minutes to mitigate market shocks. So far this year, buy and sell sidecars have been triggered 17 times on the KOSPI market, the most since the 2008 global financial crisis.
Korea's investing culture, which favors short-term trading, is also a factor. According to the Financial Supervisory Service, in Apr., the KOSPI market's average daily turnover rate was 1.48%, 6.7 times that of the U.S. S&P 500 (0.22%) and four times that of Japan's Nikkei (0.37%). The KOSDAQ market's turnover rate was even higher at 2.56%.
Turnover is a figure that divides trading volume over a set period by the number of listed shares; the higher it is, the more frequently shares change hands. This means short-term trading—buying and selling over short periods—is active in the domestic market.
◇"The person next to me only watches prices"… complaints about work disruptions
The problem is that frequent stock transactions can lead to work disruptions. B, who works as a nursing assistant at a hospital, complained that a junior staffer constantly checks MTS, disrupting patient service.
B said, "Sometimes they stand there looking at MTS even with a patient in front of them," adding, "When I asked them to refrain, they said, 'I do all my work and then look,' so I'm debating whether to report it separately to the director."
Some local governments have even faced allegations that public servants trade stocks during work hours. In Jan. this year, a resident who visited a government building in the greater Seoul area reportedly filed a complaint, saying employees had stock trading screens open on personal tablet PCs.
◇Repeated trading during work may be grounds for discipline
Experts say companies can impose sanctions if stock transactions during work hours actually disrupt work. If most of the workday is spent checking prices or trading, causing delays, missed reports, or disrupted customer service, it can be deemed neglect of duty. Repeated use of stock sites and related apps on company PCs or work devices can also be grounds for discipline.
The risk is greater for roles with potential conflicts of interest, such as finance, investment, and accounting, or if a company has rules that "ban investment activities such as stock trading during work hours." However, it is hard to justify severe discipline solely for making one or two trades during work hours. For heavy measures such as dismissal to be upheld, factors such as the severity and frequency of disruptions, the worker's rank and duties, and whether company rules were violated must be considered together.
Supreme Court precedents also hold that when judging the legitimacy of discipline or dismissal, factors such as the worker's rank and duties, work attitude, and the repetition of violations must be reviewed together. In practice, the key criterion is likely to be whether repeated and sustained price checking and trading, rather than one-off transactions, interfered with work.
Attorney Hong Kyung-yeol at Law Office Yulseon said, "Stock trading during work hours often goes beyond one-off transactions, involving continuous monitoring of market conditions and focusing on trading," and added, "In the process, problems can arise with concentration and work attitude."
Hong added, "It may be excessive to discipline someone solely for making one or two stock transactions, but if repeated disruptions to work have accumulated, that can be just cause for discipline."