Citigroup and Caterpillar slide while Overstock rises

Stocks that moved substantially or traded heavily Friday:

Overstock.com Inc., up $3.05 to $41.65

The online discount retailer said a private equity firm is investing in its blockchain business.

Citigroup Inc., down $1.72 to $70.26

Bank stocks fell as interest rates turned lower.

Banco Santander SA, down 18 cents to $5.19

European banks suffered steep losses as investors worried that financial turmoil in Turkey will spread to them.

Caterpillar Inc., down $2.60 to $135.92

Industrial companies took sharp losses Friday as the U.S. dollar strengthened.

Dropbox Inc., down $3.38 to $31.05

The online file sharing company said its chief operating officer will step down in September.

Microchip Technology Inc., down $10.67 to $87.41

The chipmaker forecast weaker quarterly revenue than analysts expected.

Express Scripts Holding Co., up $1.82 to $83.64

A shareholder advisory firm said it supports Cigna's plan to buy Express Scripts.

Stamps.com Inc., up $7.40 to $255.50

Smaller and more U.S.-focused companies did better than the rest of the market as multinationals struggled.