LIGHTSUM gained considerable attention even before debut thanks to their agency, Cube Entertainment—home to major idols like HyunA, 4Minute, and i-dle. Their 2021 debut with Vanilla seemed promising, bolstered by a lineup that included Chowon, Nayoung, and Yujeong, who ranked 13th, 12th, and 51st respectively on the hit survival show Produce 48.
The group also had a “secret weapon”: Juhyeon, who placed in the top 25 on The Unit and is considered one of 4th‑gen’s strongest female dancers. With standout visuals and top-tier performance skills, she was expected to help lead LIGHTSUM to success. However, the group soon lost momentum and slipped rapidly behind the fierce competition in the girl‑group market.
Recently, concerns exploded within SUMIT, the group’s fandom, when Cube unexpectedly announced the termination of LIGHTSUM’s official fanclub service. The company stated that sales for the SUMIT MEMBERSHIP ended on October 30, and all fanclub operations will officially shut down on November 19, 2025. While no new memberships will be accepted, current members may access exclusive content until the closure date.
With less than a week before the shutdown, fans are growing worried about the group’s fate. Although Cube did not specify LIGHTSUM’s future, the timing and wording of the announcement felt abrupt and puzzling. Many believe the notice foreshadows disbandment or an indefinite hiatus. In K-pop, shutting down a group’s official fanclub is widely seen as a grim sign.
Unfortunately, the decline had been evident. Over five years, LIGHTSUM released four EPs and single albums. With each comeback, sales dropped drastically—from 69,000 copies (Vanilla and Light a Wish in 2021) to just 19,000 for Honey Or Spice, a staggering 70% drop. At one point, Honey Or Spice sold only 822 copies in a day compared to 4,971 copies on release day—an 80% decline.
These numbers indicate that the group’s revenue has not been enough to offset production costs. In cases where artists continuously lose profit, agencies often shift focus to new trainees, leaving struggling groups inactive until contracts expire. For LIGHTSUM, contract termination is now a very real possibility.
Many fans believe the issue is not the members but the lack of strategic direction. Despite having strong performers like Chowon, Nayoung, and Juhyeon, the group never established a distinct musical identity. Their songs lacked the staying power needed to compete with dominating 4th‑gen acts such as IVE, NewJeans, aespa, and even their own seniors i-dle.
Cube Entertainment has also been criticized for insufficient promotion—sporadic comeback schedules, underwhelming music videos, lackluster visuals, and minimal marketing efforts. With fading public interest and weak content support, the group’s decline became inevitable.
Some speculate that if LIGHTSUM disbands, Juhyeon and Chowon may be the only members with a chance at staying in the industry, either as soloists or re-debuting under Cube, given their strong skills and visuals.
Despite debuting under a major agency with high expectations, LIGHTSUM could not sustain their early buzz. Without a clear concept or impactful music, they struggled to stand out in the saturated girl-group landscape.
On November 19, the industry will likely receive a definitive answer—a moment that may mark the official end of LIGHTSUM.
Sources: kenh14
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