Ah. I think I figured it out.

> FOX is acquiring Roku in a cash-and-stock transaction valued at $160.00 per ROKU share. FOX will pay $96.00 in cash and 0.9693 shares of FOX Class A common stock for each Roku Class A and Class B share outstanding immediately prior to the effective time of the merger.

So not a straight $160/share cash, but $96/share cash and some FOX shares. Roku trading below 160 means the fox stock is not considered worth (160-96) by the market.

Fox also took a dive today. While $160 total could happen, seems likely to shortchange Roku shareholders.