I wouldn't be so quick to fold there.  With antes involved a good regular is going to be raising in his position with a fairly wide range.  The HUD tool could be a little misleading because most good players start tight early then get progressively more aggressive once the antes are involved meaning he may start a tournament 10/5  but he could be as aggro as 35/25 now, to make the average be 23/16.  However, he is likely much more aggressive than that in this spot imo.  When you 3bet him, he has to call 1800 more to win a pot that contains more than 5K so I also think he will call with a wide range as well.  In fact, he will call 75% of the time according to his HUD, so basically he only folds his pure junk when he is 3bet.  He certainly calls with hands such as pairs, J10s, QJs, KQ, A10+.  When you don't lead out on the flop to me it looks like you're either going for pot control with a medium pair that missed the flop (eg 99) or you have some sort of draw and for some reason you don't want to get it in.  If you had complete air, you would probably cbet bluff, and if you had an overpair you would probably bet to protect your hand.  You could also be trapping with a set, so I understand his check behind, there's not a lot of value to him betting there even if he hit a piece because it would get worse to fold and he could be behind.  Then once you check again on the turn, your hand looks very weak.  You failed to bet twice in a 3 bet pot, which to me looks purely like pot control, so at that point I would bet if I had any piece of the flop.  His bet sizing on the turn looks as if he is sizing just enough to get you to fold and if you don't fold to still have enough left so that maybe he can bluff you off your hand on the river if you call on the turn.  I think the pot is already sufficiently large, and there are a lot of draws out there, so that if he had something strong he would just get it in on the turn.  It would be an overbet but it doesn't make sense for him to price the draws in.  Different bet sizes have a different impact on different people but I know that when I bluff I would size it the way he is, that way he gets two barrells at it.  Yet most likely when you check to him on the turn he bet because he had some minor piece of it and you checked to him twice!  When you called turn, I don't think he knows that you have AK, you would probably be calling with a weaker pair than that and some draws as well.  It's not as if you only ever 3bet AK, AA, KK…I'm sure there are some 3bet bluffs/3bet light in there.  The math says you should call, I think.  AQ, A10, etc. beat you with two pair, KJ beats you, and sets beat you.  But there are much more hands that you beat: single pairs involving the Queen (KQ stands out), single pairs involving the 10 are less likely but possible, weaker pairs that he called with preflop and didnt make a set, and missed draws.  You are assuming that a moderate strength hand such as KQ would just check back, but I'm not so sure.  He could be turning his hand into a bluff and it's possible given your passive line that he thinks he is value betting thin. I think some people are willing to turn their hands into a bluff here.  You are given close to 2:1 on the call and I think you're actually ahead > 50% of the time so I make the call unless I had a specific read otherwise.