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* Moderna up as late-stage study for COVID-19 vaccine begins
* Hasbro tumbles after profit miss
* Senate Republicans likely to unveil $1 trillion aid proposal
* Indexes up: Dow 0.35%, S&P 0.46%, Nasdaq 0.94% (Updates to early afternoon)
By Medha Singh and Devik Jain
July 27 (Reuters) - Wall Street's main indexes gained on Monday as investors looked past surging U.S. COVID-19 cases, betting instead on more stimulus to revive a battered domestic economy ahead of a week packed with quarterly earnings reports.
Apple Inc, Amazon.com Inc, Facebook Inc and Alphabet Inc rose between 0.5% and 0.9%, and were among the top boosts to the S&P 500 and Nasdaq. The four FAANG companies are among the 189 S&P 500 companies expected to report results this week.
About 80% of the 130 S&P 500 firms that have reported so far have beaten a low bar of earnings estimates, according to IBES Refinitiv data.
"It's probably going to be the biggest week of the year in terms of what people are expecting due to the impact from the coronavirus outbreak," said Brian Pirri, principal at New England Investment and Retirement Group in Boston.
"I don't think we're going to see a slowdown in technology stocks. There was some profit taking due to high valuations, but I don't see them going away anytime soon."
Safe haven assets were in demand with gold prices at record levels amid concerns over a diplomatic row between the United States and China, escalating COVID-19 cases in southern and western U.S. states and an unexpected rise in U.S. jobless claims last week.
Trillions of dollars in fiscal and monetary stimulus have been pivotal in bringing the S&P 500 to within 5% of its February record high.
Later in the day, U.S. Senate Republicans are likely to unveil their $1 trillion coronavirus aid package, which would be negotiated with Democrats, ahead of the expiry of enhanced unemployment benefits on Friday.
"The market is factoring in the fact that there's going to be some kind of extension of around one-and-a-half to 2 trillion dollars of total aid, and if that does not occur it would be a near-term negative catalyst," said Mike Mussio, president at FBB Capital Partners in Bethesda, Maryland.
Expectations are running low for any major announcement at a two-day Federal Reserve meeting, but policymakers are likely to lay the groundwork for more action later this year, analysts said.
At 12:48 p.m. ET, the Dow Jones Industrial Average was up 92.63 points, or 0.35%, at 26,562.52, the S&P 500 was up 14.70 points, or 0.46%, at 3,230.33. The Nasdaq Composite was up 97.49 points, or 0.94%, at 10,460.67.
Materials stocks rose 1.1%, more than any other S&P sector, boosted by the shares of gold miners. Financials , utilities and energy were the only sectors in the red.
Moderna Inc jumped 7.7% as it started a U.S. government-backed late-stage trial to assess its COVID-19 vaccine candidate in about 30,000 adults.
Hasbro Inc dropped 7.5% after the toymaker missed quarterly results estimates, hit by production shutdowns due to coronavirus lockdowns.
Advancing issues outnumbered decliners for a 1.36-to-1 ratio on the NYSE and a 1.16-to-1 ratio on the Nasdaq.
The S&P recorded 15 new 52-week highs and no new low, while the Nasdaq recorded 49 new highs and 21 new lows. (Reporting by Medha Singh and Devik Jain in Bengaluru; Editing by Shounak Dasgupta)