Credit Suisse Group AG won’t have to face class action claims that it helped rig foreign exchange rates, but some antitrust issues will be tried on a class-wide basis, a Southern District of New York judge ruled.

The lawsuit accuses 16 major banks of conspiring to widen the spread between the “bid” and “ask” prices for foreign currency. Fifteen banks settled those claims for a combined $2.31 billion, but Credit Suisse continues to fight them.

The banks’ manipulation of the daily “spot price” sent ripples across the whole foreign exchange market, according to the currency traders who consolidated their claims...