They're not obligated to; boards can pretty much do whatever they want.

However, Twitter's board doesn't use Twitter and doesn't actually seem to care about it at all, so they're not exactly going to claim to shareholders they can run it better than an offer that much above its current value.

> Twitter's board doesn't use Twitter

[citation needed]

Aren't they obligated to negotiate for a higher price? At least, they should try.

Who the heck doesn't negotiate?

How is no negotiation the best strategy?

Hmm this might be hard for you to believe but I've never negotiated in my life. I always accept asked price. Didn't realize this is not the norm. This is not in business context though.

You are not running a $30b company.

At work, I was involved in a deal with a large company. The numbers are back and forth like 10 times with adds-on and discounts. It's just standard stuff.