If you look at is closely you'll see that it might be SS-market as well.

Let's get some "Smarket" stores in the U.S. 

"Hey where're you going?"

"I need to go to the smarket."

"...."

K markets used different amount of K's for stores of different sizes. So it was something like KK Market and KKK Supermarket, KKKK Citmarket being the biggest. They dropped the KKK Supermarket because of well, Finns learning what KKK meant in America.

S markets considered using the the same system so we nearly had SS markets (The one in picture is just S market, though the logo looks like a double S).

I wonder how Germans feel about Halpa-Halli (another Finnish market) being shortened as HH, as in HH-cafe.

ISIS going strong in Finland, among others