The damage was heaviest in companies whose supply chains are most dependent on overseas manufacturing. Apple Inc., which makes the majority of its US-sold devices in China, was down about 9% in morning trading. Lululemon Athletica Inc. and Nike Inc., among companies with manufacturing ties to Vietnam, were down around 12%. Walmart Inc. and Dollar Tree Inc., retailers whose stores are filled with products sourced outside of the US, were trading lower by about 1% and around 10%, respectively.