sql - Table without logical primary key -

i've read similar questions both on google , stackoverflow, example, thread should each , every table have primary key? , understand it's idea have primary key in every table.

i'm trying create simple table, stores end of day prices list of stocks, has 3 columns: stock ticker, date , price. apparently none of these 3 columns unique , use table i'll need join on both date , stock ticker (i have unique constrain on that). of course, can add surrogate id column sake of having primary key, want check if acceptable design or there're better ways model data i'm storing?

many thanks.