NEBIUS stock experienced a significant pre-market plunge of 5.45% as investor sentiment turned bearish amid concerns over competitive threats and insider selling activity.

The decline was primarily driven by ongoing fears that Meta's plans to establish an internal compute commercialization division could create direct competition for NEBIUS in the AI compute market. Despite analyst views that Meta lacks surplus capacity to sell, the potential market entry has created a persistent overhang on the stock.

Compounding the negative sentiment, recent insider selling has further eroded market confidence. CEO Arkadiy Volozh sold a substantial number of Class A shares, partially to cover tax obligations on restricted stock units, while two other executives collectively disposed of over 50,000 shares. This cluster of insider disposals has left the stock vulnerable to continued downside momentum in the near term.