Legality of peer director short selling

Hypothetically speaking, I would be interested in everyone's thoughts on whether a director of one company can legally short sell it's peer.

Whilst there are clear ethical and reputational concerns for that director and/or that company, I am not convinced it breaches any law.

To be clear, this topic is general in natural, yet has been posted under the TON thread due to alledged historical manipulation. Whilst I acknowledge the at times strange trading of this share I personally have no knowledge of any manipulation; first, second or third hand.

This thread is not designed to bait or inflame or create any hostilities with any of TON's peers and/or it's directors or shareholders.