Is that legal ? I guess it is. Can't you just say "no" and not come up with an excuse ?
That was my first thought. I'm sorry, no. That offer is between them and me, and I'm not comfortable sharing information that isn't owned solely by me. All you need to take out of it is that that offer is my current lower bar and, if you're not willing interesting in negotiating based on it, then we're probably done here.
> I worked at a company where HR would request a copy of the competing offer
"I'm sorry, but the offer is from a stealth startup who does not wish their name to be known."
> it was kind of shocking to learn how often candidates lied about everything from where they worked in the past to having competing offers.
That's the real gut punch. Honest hard-working people are getting shafted while liars and thieves get ahead.
HR eventually just assumed the mythical competing offer was a bluff, and to be honest from everything I saw that was most likely correct for the average applicant.
As someone who always interviewed and negotiated honestly, it was kind of shocking to learn how often candidates lied about everything from where they worked in the past to having competing offers.