NEW YORK (MarketWatch) — U.S. stocks climbed on Monday, with the S&P 500 extending its longest win streak since July, after Chinese exports beat projections and as investors anticipated the unveiling of Apple Inc’s new iPhone models.

The Dow Jones Industrial Average rose nearly 166 points and finished up 140.62 points, or 0.9%, at 15,063.12, its best performance in more than eight weeks. Caterpillar Inc. CAT, +1.07% led gains that included all but one of the blue-chip index’s 30 members after the Chinese government reported exports rose 7.2% in August from the year-earlier period, topping forecasts for a 6% rise.

“China came out with significantly better economic data over the weekend, and that’s important to us because the China demand story continues to be a very important piece of the global economic picture,” said Art Hogan, market strategist at Lazard Capital Markets.

Apple, Delta, Molex: 3 hot stocks

Helping lift equities to afternoon highs were reports related to Syria, with Russian Foreign Minister Sergei Lavrov saying his nation had called on Syria to relinquish its chemical-arms stockpile if the move would help prevent a U.S.-led military strike.

A top aide to President Barack Obama said the White House would take a “hard look” at Russia’s proposal for Syria to put its chemical weapons under international control. The “chatter that a negotiated settlement for Syria’s chemical weapons might be a possibility” bolstered equities, said Michael Sheldon, chief market strategist at RDM Financial.

The S&P 500 index SPX, -0.49% climbed 16.54 points, or 1%, to 1,671.71, with materials and information technology pacing broad gains that included all of its 10 major industry groups. The Nasdaq Composite index COMP, -0.82% rose 46.17 points, or 1.3%, to 3,706.18.

Apple Inc. AAPL, -2.10% , a heavyweight on the S&P 500 and Nasdaq, rose 1.6% before an investor event where the iPhone maker will unveil upgraded versions of its smartphone.

“There’s excitement about the Apple product announcement tomorrow,” said Lazard’s Hogan. “And volumes are low and participation is still timid, so any moves get exaggerated, very much like we saw in the volatility on Friday,” he said of the end-of-week session, which had the Dow average crossing zero 11 times.

Molex Inc. US:MOLX jumped nearly 32%, leading S&P 500 gainers, after the manufacturer of electronic components for products including Apple’s iPhone agreed to be purchased for $7.2 billion by Koch Industries Inc., the holding company run by the billionaire Koch brothers.

Delta Air Lines Inc. DAL, -2.17% gained 9.4% after S&P Dow Jones Indices said the carrier would replace BMC Software Inc. US:BMC in the S&P 500.

Apple is expected to unveil two new iPhone models at events set for Tuesday. Bloomberg

For every stock on the decline, roughly four rose on the New York Stock Exchange, where almost 639 million shares traded.

Composite volume breached 3 billion.

The thinly traded market comes in a “historically difficult month” for stocks, and follows a trend that had “a significant amount of risk” coming out of equities in August, with the S&P 500 losing 3.1%, noted Hogan.

While many Wall Street professionals are back at their desks after summer breaks, the low volume and high volatility is likely to continue “until we get resolution in a lot of the September issues,” said Hogan.

With Congress back in session, those issues include potential U.S. military strikes against Syria, the budget-debt ceiling and approving a replacement for Federal Reserve Chairman Ben Bernanke, with President Barack Obama expected to nominate someone in coming weeks.

Treasury yields fell, with the benchmark 10-year note used in figuring mortgage rates and other consumer loans off two basis points at 2.918%.

The dollar fell against the currencies of major U.S. trading partners including the euro EURUSD, +0.06% but excluding the Japanese yen USDJPY, -0.28% .

The cost of energy declined, with a barrel of crude CLV23, priced at $109.52 a barrel, down $1.01, or 0.9%, on the New York Mercantile Exchange.

Gold futures GCZ23, gained 20 cents to $1,386.70 an ounce.

Wall Street on Friday finished higher for the week as reports indicated increased global economic growth even as investors weighed possible U.S. military action in Syria and chances of the Federal Reserve cutting back on its monetary stimulus later in the month.