Any suggestions...

Oh man, that stinks. Literally. We used to have a Persian that would put his front paws in the litterbox and poop outside of it. He would also pee on the carpet next to the litter box. Never actually made it inside. We never figured out why he did this and eventually had to give him away.
Maybe you could call the vet and ask them? They might want to take a look at him? Hope you get it figured out soon! Cat pee stinks!

My kitty Ashley does this and the vet told me it was a behavorial thing and I might not ever get her to stop. She poops right next to the litterbox. I can give you a few suggetions that might help. First if this is brand new behavior take him to the vet to make sure there are no problems causing this behavior. Next I would ask if you have moved, added a new furbaby to your home or chaned routines. Stress can cause these kind of problems. If you changed litter or litter boxes this can cause this behavior too. If you switch products then you might want to switch back, you could also try cleaning the litterbox, maybe it has residual smell that we can perceive but you kitty can. Otherwise you may be like me and be forever cleaning up poop off the carpet.

Cats that start doing this, after never doing it, may be because:
1: Kitty litter is not clean
2: Kitty litter is in front of everyone.
3: They are sick
4: They are stressed out from another pet
Do not hit it. Try to figure out the problem. If you catch him making there, spray him with water and say no.
Consider going to the vet if it persists. Good luck.