Tablet giants Apple, Samsung feel heat as competitors gain steam

When a company saturates its home market with a once-hot product, expect it to pump up its presence in foreign lands to keep the momentum going.

That old-time tactic is proving tough in tablet computers, where leaders Apple and Samsung are under heavy pressure in emerging markets from China’s Lenovo, Taiwan’s ASUS, and other tablet upstarts.  

Apple iPad shipments took a dive in the last quarter ended in June, down 9.3%. South Korea’s Samsung recently reported a quarterly tablet  shipment increase of only 1.6%. Lenovo and ASUS, meantime, were up 64.7% and 13.1%.

Both companies continue to dominate the global tablet market – heading toward $85 billion this year,...