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* Walmart rises on strong Q1 results
* Advance Auto Parts gains on same-store sales potential
* Home Depot drops after results miss estimates
* U.S. housing starts post record decline
* Indexes mixed: Dow up 0.25%, S&P flat, Nasdaq up 0.55% (Updates to early afternoon)
By Medha Singh and Ambar Warrick
May 19 (Reuters) - The S&P 500 was largely unchanged on Tuesday, after a strong rally in the prior session, as investors sifted through a mixed batch of results from major retailers including Walmart and Home Depot.
Home improvement chain Home Depot fell 2.4% as it missed quarterly profit estimates due to higher costs, while department store operator Kohl's Corp slumped 7.8% after reporting a bigger-than-expected loss.
Walmart Inc, on the other hand, rose 0.8% after the world's largest grocer exceeded expectations for quarterly revenue and earnings as online sales soared due to stockpiling of essentials during the coronavirus-led lockdown.
The S&P 500 retailing index was up 0.7%.
Trillions of dollars in stimulus has helped the S&P 500 rebound more than 34% from its March lows. Although it is now just about 13% below its record high, the pace of the rally has slowed in May owing to uncertainty over the outbreak and rising U.S.-China tensions.
"Volatility is going to be with us for some time. There's a leveling off process where people accept the new normal, or they just abandon hope," said George Young, portfolio manager of the Villere Balanced Fund in New Orleans, Louisiana.
The benchmark index climbed more than 3% on Monday, boosted by promising early stage data for a potential COVID-19 vaccine and Federal Reserve Chair Jerome Powell's pledge to support the economy as needed until the current crisis has passed.
Powell, in his testimony to the Senate Banking Committee on Tuesday, said the central bank was continuing to consider ways to accommodate additional borrowers, and that Congress should consider anything to keep people out of insolvency.
"By far the biggest focus for markets are variables attached to medical news, (followed by) actions from central banks and fiscal policymakers," said Tim Shaler, chief economist for iTrustCapital in Newport Beach, California.
At 12:26 p.m. ET, the Dow Jones Industrial Average was down 60.41 points, or 0.25%, at 24,536.96, the S&P 500 was up 1.69 points, or 0.06%, at 2,955.60. The Nasdaq Composite was up 50.49 points, or 0.55%, at 9,285.32.
Gains in technology focused companies, including Amazon.com , Apple Inc and Intel Corp, were some of the biggest boosts to the S&P 500 and the Nasdaq.
Seven of the 11 major S&P sectors were trading lower, led by real estate and energy stocks. Technology and consumer discretionary posted the biggest percentage gains.
Advance Auto Parts climbed 5.8% after the company said same-store sales improved significantly at the start of the second quarter.
The S&P 1500 airlines index advanced 2.5% as two top U.S. airlines and Air Canada said ticket cancellations were slowing and demand was showing signs of improvement since the coronavirus pandemic brought global travel to a virtual standstill last month.
Advancing issues outnumbered decliners by a 1.23-to-1 ratio on the NYSE and by a 1.05-to-1 ratio on the Nasdaq.
The S&P index recorded 10 new 52-week highs and no new lows, while the Nasdaq recorded 50 new highs and six new lows. (Reporting by Medha Singh and Ambar Warrick in Bengaluru; Editing by Patrick Graham, Arun Koyyur and Sriraj Kalluvila)