No they don't, this is tax fraud and illegal. Companies are not allowed to claim donation round-ups as their own for tax purposes. They may match donations, which they can claim, but they cannot claim money they did not spend as their own donations. You, however, can, if you keep your receipts.
"Just because it's illegal doesn't mean they don't do it" -- Fair point, but this is the IRS we're talking about. I doubt big business are willing to fuck around that particular avenue. Other avenues, definitely.
And just like Reddit, the quickest way to get accurate information is to post inaccurate information and then get 10 super snarky corrections by know it alls in the comment replies!
Then to be even more like reddit, we have a confidently incorrect asshole spreading easily googleable misinformation who is somehow now -- plot twist -- the fucking victim. Because yeah that's how this shit works. We should all just spread lies because anyone who corrects us is the real asshole! Make sure you never fact check yourself people! It's just too burdensome. Just say shit and get mad later if you're corrected