By Caitlin Ostroff

U.S. stocks rose in early trading Thursday, following the S&P 500's best six-month performance since 2009, as central banks' stimulus measures keep markets buoyant.

The S&P 500 gained 0.8%, indicating that the broad market gauge could climb on the first day of the fourth quarter. Despite a decline in September, the benchmark was up about 27% over the two quarters ended Wednesday. The Dow Jones Industrial Averge opened 176 points, or 0.6%, higher, while the tech-heavy Nasdaq Composite Index added 1.1%.

Shares of Boeing rose 2.8% after the plane maker got a tentative personal endorsement for fixes to its beleaguered 737 MAX from the head of the Federal Aviation Administration. Shares in PepsiCo gained 0.4% after the drinks and snacks company beat earnings estimates. Conagra Brands shares rose 2.2% Thursday after its board raised the quarterly dividend.

Some investors are hopeful that an economic rebound in recent months will have resulted in corporate earnings that beat expectations for the third quarter. Appetite for risky assets that typically generate higher returns -- including stocks -- continue to be buoyed by the flood of cheap money unleashed by central banks and governments.

"If you look at the market, it's telling you that we're going to get a recovery next year. I'm convinced we're in a new bull market," said Patrick Spencer, managing director at U.S. investment firm Baird. "Even with the election, behind all that is central banks and liquidity."

Coronavirus infections are another point of focus. Infection rates in the U.S. have remained elevated for some months, and health experts have warned that the colder months may bring a new wave of cases. While investors don't expect to see a repeat of the spring's stringent lockdowns, fresh restrictions could threaten recovery in the labor market and weigh on consumer spending, which accounts for more than two-thirds of the U.S. economy.

About 837,000 Americans applied for new unemployment benefits through the week ended Sept. 26, down from 873,000 the week before, signaling an improving labor market though unemployment remains high. New figures from the Department of Commerce showed that U.S. consumers boosted spending by 1% in August from the month prior.

Investors continue to assess whether Congress will pass another aid package that would bolster U.S. economic growth ahead of the elections, though such hopes have largely receded in recent weeks.

A renewed burst of optimism this week -- prompted by talks between Republican and Democratic leaders -- began to fade on Wednesday after the House postponed a vote on a $2.2 trillion package. Democrats are trying to find common ground with the White House on a bipartisan agreement, though they remain far apart on key issues.

"The big wildcard in the U.S. is whether we get more fiscal spending or not," said Gregory Perdon, co-chief investment officer at private bank Arbuthnot Latham. "The political backdrop is just so toxic."

The Institute for Supply Management's September purchasing managers index for manufacturing, due out at 10 a.m., is likely to reflect a strong rebound in factory activity amid a slow global recovery and strong domestic demand for autos, electronics and other goods.

In bond markets, the yield on the benchmark 10-year Treasury ticked up to 0.714%, from 0.677% Wednesday.

The ICE U.S. Dollar Index, which measures the greenback against a basket of currencies, fell 0.2%.

Overseas, the pan-continental Stoxx Europe 600 edged up 0.2%.

Among European equities, shares in Bayer fell almost 10% after the German chemicals and pharmaceuticals company said the coronavirus pandemic would hit its crop-science business harder than anticipated as prices for various crops fell.

STMicroelectronics rose 6.5% in Milan after the chip maker raised its 2020 revenue outlook following stronger-than-forecast third-quarter revenue.

In Asia, the Tokyo Stock Exchange halted all stock trading for Thursday due to a system problem, and said it expects to resume normal trading Friday. Markets in China, Hong Kong and South Korea were closed for a holiday.

Write to Caitlin Ostroff at caitlin.ostroff@wsj.com

(END) Dow Jones Newswires

10-01-20 0947ET