STOCKS GET CRUSHED: Here's what you need to know

It was an ugly day for the markets, as each of the major US indexes dropped nearly 3% to start September, traditionally the weakest month of the year for the stock market.

Oil got slammed Tuesday, falling 8% with West Texas Intermediate crude prices falling back near $45 a barrel after a 30% runup in just three days saw WTI erase almost all of its August losses.

Stocks started the day deep in the red, and the selling pressure hardly relented at all into the closing, sending stocks out on their lows for the second straight Tuesday.

First, the scoreboard:

• Dow: 16,058, -470, (-2.8%)
• S&P 500: 1,913, -58, (-2.9%)
• Nasdaq: 4,636, -140-, (-2.9%)

And now, Tuesday's top stories:

1. It was ugly from the get-go. US stocks opened the session down about 300 points and never found solid footing, sliding throughout the day and finishing near their lows of the session. About 99% of the S&P 500 finished in the red, one of the broadest down days for stocks in the last 20 years. Overnight, data out of China showed manufacturing activity declined further in the world's second-largest economy, while Korean exports, often seen as an indicator of China's economic strength, plunged nearly 15% from August 2014.
2. Crude oil was all over the place again, getting slammed Tuesday after a huge rally over the last three days that saw oil wipe out almost all of its August losses. The three-day, 30% rally, however, wasn't based on anything having to do with the fundamentals of oil, according to Citi's oil expert Ed Morse. Morse was particularly critical of the market's reading of an OPEC Bulletin posted Monday that suggested the cartel stood ready to talk to other producers.
3. On the US economic front, that data continued to be encouraging, with US auto sales in August rising to their fastest pace in a decade, hitting an annualized pace of 17.7 million vehicles. Among the notable manufacturers posting better-than-expected sales growth in August were Ford, with sales up 5.6%, and Fiat Chrysler, which reported a sales rise 1.7% in August after economists had forecast a decline.
4. Construction spending data for July also came in better than expected, with spending rising 0.7%, topping expectations. Residential construction rose 1.1% in July and 15.8% against the prior year. In a note following the report, Ian Shepherdson at Pantheon Macroeconomics said, "In one line: Booming." Shepherdson added that the "overall impression from the past few months is that the construction sector overall is the strongest part of the economy, with spending up at a remarkable 26% annualized rate in the three months to July, compared to the previous three months."
5. Manufacturing data in the US, however, came in a bit softer than expected. Markit's manufacturing PMI reading came in at 53.0 for August, down from July's reading, while the Institute for Supply Management's manufacturing PMI fell to its lowest level since May 2013.
6. Canada's economy fell into recession in the first half of the year, with annualized gross-domestic-product growth in the second quarter falling 0.5%, while the first quarter's figure was revised to show the economy shrank 0.8%. The decline in commodity prices, particularly oil, is weighing on Canada's economy, and BNP Paribas economist Derek Lindsey said in a note to clients that the negative impact from this slide isn't likely to go away anytime soon.
7. In company news, McDonald's announced Tuesday that, starting October 6, it will begin offering breakfast all day. This move from McDonald's comes as it tries to stabilize flagging sales in the US.

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