[s1artibartfast]

Sorta, there are no SEC requirements for lockup. It is all depends on the agreement between the IPO company and the IPO underwriters syndicate. Spotify and Slack notably skipped lockup entirely.

Goldman Sachs, Morgan Stanley, BoA, ect are the ones who set the IPO lockup terms based on their risk and exposure post IPO.

Indexes, exchanges, underwriters, ect are all private institutions who mostly can and do set their own rules.

[fsuts]

The terms are public so you can read them

Something like 20% can be sold after the q2 results are released

[s1artibartfast]

I am fully aware of the terms. There are lots of schedules. I was speaking to the origins of "prohibitions".

It is also worth noting that typical lockup contracts can be waived early at the sole discretion of the underwriters.