SNSD had 9 members, one of which was “ice princess” Jessica Jung. Her biological sister is Krystal in the group f(x). Over time, it became apparent to fans that relations between Jessica and the other members of SNSD were less than perfect. If you watch video of them over time, you’ll see that she stopped interacting with warmly with the others, especially Taeyeon.
Over time Jessica also earned the name “lazy sica” because on stage she began to look like she didn’t care. Jessica is the one dressed in all black with the black hat in this practice video. Judge for yourself whether you think she is dancing with as much effort and power as the other members.
In 2014 Jessica and Krystal had a reality show on a cable channel. I watched it. It was meh. In one episode Tiffany and Hyoyeon made an appearance. Also in one episode Jessica can be heard humming the song “Catch me if you Can”, which had not been released at the time. There was a promotion on social media to #CatchGG, but then the song did not appear in a timely fashion after that promotion.
In September of 2014 Jessica posted on Instagram something along the lines of “I’ve been informed I’m no longer a member of SNSD, wtf.” It was confirmed later that day she really was no longer a member. In April 2015 the song “Catch me if you Can” was finally released. Someone illicitly uploaded an older version of the music video that included Jessica. This shows that the timing and manner in which she left the group was definitely not part of the plan.
The exact details of how and why she was kicked out were never made public. Whenever anyone gets asked about it, including Jessica, they give a dodgy answer. The most common explanation I’ve seen is that she was planning to leave gracefully at some point soon anyway. However, because she was neglecting her duties to SNSD in favor of the fashion company she was starting, they kicked her to the curb. I’m sure bad relations with the other member didn’t help either. I also heard she didn’t show up for some practices. All the other members have plenty of non-group activities. Yoona even recorded some crazy long TV show in China for big money. But they always made SNSD the highest priority.
Nowadays Jessica lives the life of a rich person who owns a small fashion company and occasionally releases solo music. She can’t promote her music in Korea or appear on TV easily because presumably, her old company keeps her out. But she can still make MVs and release music. You’ll often see her in the crowd at major sporting events like the NBA Finals or Mayweather fights.
You will see fans online use the term OT9 to refer to the “One True 9” originaly SNSD lineup. Implying that the 8 member SNSD is just not the same. Also, now 3 members of SNSD have left SM entertainment, but they still insist the group has not disbanded. The future is uncertain.