The ongoing strike, the first in the electronics company’s history, involved only a small fraction of its workforce and lasted less than a month.

Thousands of unionized workers at Samsung Electronics in South Korea, who began an indefinite strike last month, returned to work by Monday after failing to secure concessions from the tech giant. This strike, the first of its kind in Samsung’s decades-long history, involved around 6,500 employees—just a small fraction of the total workforce and union membership. According to Lee Hyun Kuk, vice president of the Nationwide Samsung Electronics Union, most strikers had resumed their duties by Monday.

Negotiations between the union and Samsung over wages, bonuses, and vacation days had been ongoing for months without resolution. In June, the union held a one-day strike as a warning before commencing the indefinite strike in July. Throughout the dispute, Samsung maintained that operations would remain unaffected, a stance it reiterated last week.

The financial strain of a prolonged, unpaid strike led union leaders to call for a return to work. Although the union’s strike fund totals approximately 80 million won (about $60,000), it has not revealed whether these funds were used.

“After 25 days on strike, we still have no results,” Son Woo-mok, union president, told members. “I feel responsible as the leader for not delivering any results to those who have been striking without pay.”

The union, which has over 31,000 members, plans to implement guerrilla strikes, or surprise walkouts, but has not specified their frequency or number. “This is not a defeat, but a tactical shift,” Mr. Son said.

Union leaders also held a press conference outside the home of Samsung’s chairman, Lee Jae-yong, in Seoul, urging him to address their concerns. However, Mr. Lee was in Paris, attending meetings with other business leaders during the Olympics.

Despite the strike, Samsung launched its latest electronic devices, including the Galaxy Fold 6 phone and new smartwatches, on schedule last month. The company’s electronics division employs about 260,000 people globally.