Important stocks are being published today.
Also works. :-)
So, being a non native english speaker, is 'are released' valid ?
It's only valid in a narrative context, such as a news announcement. Otherwise one would use the present progressive: “Important stocks are being released today.”.
I think "stocks are offered" is the most common way to express this. .
“Important stocks are released today.” means today is the first time they're available. “Important stocks are offered today.” doesn't.
You are correct.
Seems fine. It's passive voice.
Yes, "are released" and "are being released" are equivalent and equally valid in this context.