Transfermarkt says that Fenerbahçe is currently the most valuable team after the recent transfers.
Source: https://www.transfermarkt.com/super-lig/startseite/wettbewerb/TR1But so far Galatasaray have started better. However I can't say they played amazingly in all of those matches. Especially giving the Karagümrük match as an example.

Bookies are showing them a solid favourite for the Super League trophy once again. But it's a long journey of course. Let's see how they balance the league and CL at the same time...
There is a bit of a trick there, that's the reason. When you look at the names and how they are playing, you will see that most of the players at Galatasaray has higher value than what transfermarkt says, because they are great players and performance is higher, and when you compare it to players at Fenerbahce, they are higher valued while not giving the same performance.
It's sort of like Manchester Uniter situation, they finish 15th and yet they are still considered higher in value. Value is not worth, those are not equal things, which is why you do not see players being sold for what they are valued on that website, it's usually either higher or lower. Messi is considered to be valued 18 million for example, because that is his "value", do you really think you can offer Miami 18 million and get Messi? You think Miami would accept that offer?