UBS has downgraded Pilbara Minerals (ASX:PLS), IGO (ASX:IGO), and Liontown Resources (ASX:LTR) due to falling lithium prices, according to the investment bank's website.

As of May 30, lithium prices have declined by 19% year to date and by above 42% year-on-year to 60,700 Chinese yuan per tonne.

UBS has downgraded IGO from neutral to sell with a reduced price target of AU$3.60 from AU$4.30.

The investment bank has also downgraded Pilbara Minerals from neutral to sell with a reduced price target of AU$1.10 from AU$1.30, while Liontown Resources has been downgraded from neutral to sell with a price target of AU$0.50, down from AU$0.65.

Shares of IGO and Pilbara were down around 6%, and Liontown Resources was down about 3% on market close.