NEW YORK (REUTERS) - US stocks ended down on Tuesday (May 18), slumping on a sharp decline in telecom stocks and weak housing starts data that overshadowed better-than-expected earnings from Walmart and Home Depot. AT&T Inc shed 5.8%, among the biggest percentage decliners in the benchmark S&P 500. It extended declines from Monday, when the telecoms firm said it would cut its dividend payout ratio as a result of its $43 billion media asset deal with Discovery Inc. T-Mobile and Verizon Communications also dropped 3.71% and 1.31%. Eight of 11 major S&P sectors ended the session in the red, with Energy and Industrials having largest percentage decline, according to Refinitiv data. Utilities were basically flat. The three main indexes opened higher after Walmart, the world's biggest retailer, raised its full-year earnings forecast and Home Depot reported quarterly same-store sales above estimates. "Those are both emblematic of strength in the corporate sector and also of the consumer. I mean, you can't have Walmart and Home Depot have blowout earnings without the consumer really stepping up spending stimulus checks, adopting ecommerce, as well as getting back into stores", said Ross Ma...