Skydance and Paramount will merge. Paramount class B share will be bought at $15. Why would the market react badly at the news?

Skydance will buy Redstone’s holding company. Afterwards, it will merge with Paramount Global. The current owner of class B share can either sell their share at $15, or receiving a share of the new company. And the stock drop 5% at opening hour.

What am I missing here?