US STOCKS-S&P stumbles as Moderna sinks on report questioning trial results

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* Walmart posts strong Q1 results but gains fade
* Home Depot drops after results miss estimates
* Moderna drops after report questions trial data

(Updates to market close)
By Chuck Mikolajczak
NEW YORK, May 19 (Reuters) - The S&P 500 closed lower on
Tuesday, as investors focused on a report questioning Moderna's
recent coronavirus vaccine early-stage trial results, wiping out
modest gains on the benchmark index in the last hour of trading.
Major averages fell to session lows in the wake of a report
from STAT News that questioned the validity of the results of
Moderna's vaccine trial, which the company had announced Monday.
Moderna shares plunged about 10% after the report.
"The market is keen on health-care news much more than it is
on economic data," said Art Hogan, chief market strategist at
National Securities in New York. "We are largely baking in the
second quarter being down significantly – GDP growth rates,
earnings, economic data – but what we don't know, what will
drive markets will be incrementally good news on the healthcare
front."
Stocks had initially edged higher as investors attempted to
glean information from a mixed bag of results from major
retailers.
Home improvement chain Home Depot HD.N fell after it
missed quarterly profit estimates due to higher costs, while
department store operator Kohl's Corp KSS.N tumbled after
reporting a bigger-than-expected loss. Walmart Inc WMT.N , on the other hand, exceeded
expectations for quarterly revenue and earnings as online sales
soared as consumers stockpiled essentials in response to
coronavirus lockdowns. Still, its shares finished down after
rising as much as 3.4% earlier. "Everyone wants to take every retailer's report of being
indicative of something, but at the same time staying open and
doing stuff is good, it costs to do that," said Willie Delwiche,
investment strategist at Baird in Milwaukee.
Advance Auto Parts AAP.N climbed after the company said
same-store sales improved significantly at the start of the
second quarter, helping to lift the S&P retailing index.

Trillions of dollars in fiscal and monetary stimulus have
helped the S&P 500 rebound nearly 35% from its March 23 intraday
low. While the benchmark index is now less than 13% below its
Feb. 19 closing record, gains have largely slowed in May on
uncertainty over truly halting the spread of the coronavirus and
allowing business to resume and rising U.S.-China tensions.
The benchmark index surged more than 3% on Monday, boosted
by Moderna's promising early-stage data for a COVID-19 vaccine
and Federal Reserve Chair Jerome Powell's pledge over the
weekend to support the economy as needed until the crisis has
passed.
Powell, in 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.
Unofficially, the Dow Jones Industrial Average .DJI fell
1.56% to end at 24,213.76 points, while the S&P 500 .SPX lost
1.03%, to 2,923.48. The Nasdaq Composite .IXIC dropped 0.52%,
to 9,186.97. 2,923.48.
The Nasdaq Composite .IXIC dropped 0.52%, to 9,186.97.