It's been a bad 24 hours for tech companies, oil prices are lifted by the apparently increased chances of a deal in Algiers, and it's PMI day in Europe.

Facebook Inc. has been giving advertisers an inflated metric for the average time users spent watching a video — by not counting people who viewed for less than 3 seconds. Shares in the company fell 1.5 percent in extended trading. Yahoo! Inc. said it suffered an attack in 2014 in which the personal information of at least 500 million users was stolen. The revelation of the hack comes ahead of Verizon Communications Inc.’s planned acquisition of Yahoo's web portal assets. Finally, Twitter Inc. was downgraded by RBC Capital Markets Analyst Mark Mahaney to "underperform" as a proprietary survey showed advertisers plan to cut back spending on the site. 

A barrel of West Texas Intermediate for November delivery jumped as much as $1.00 to $46.41 this morning after Reuters reported that Saudi Arabia was ready to cut production if Iran agreed to a freeze. Former Algerian Energy Minister Chakib Khelil said he is confident that OPEC will reach an agreement at the meeting next week in Algiers. As the global oil surplus to continues to grow, the pressure for an accord increases.

IHS Markit's monthly composite Purchasing Managers Index for the euro area fell slightly to 52.6 for September, from 52.9 in August, showing growth in the currency bloc is still struggling to gain traction. At a national level, there was a surprise in the German data, where services PMI came in at 50.6, well below the 52.1 expected by economists surveyed by Bloomberg. Markit's U.S. manufacturing PMI is due to be released at 10:00 a.m. ET, with expectations for a reading of 52.0, unchanged from August's figure.

Overnight, the MSCI Asia Pacific Index dropped 0.2 percent, with Japan's Topix index also slipping 0.2 percent as concerns over the strength of the yen weighed on exporters. In Europe, the Stoxx 600 Index was 0.6 percent lower at 6:15 a.m. ET. A Bank of America Corp. report showed fund managers have withdrawn money from the region’s equities for a 33rd straight week. S&P 500 futures were down 0.1 percent.

Three months ago today, polling opened in the U.K.'s referendum on membership of the European Union. The latest warnings on the fallout from the result of that poll include a risk to 100,000 jobs in London, if the City loses its dominant role in clearing, claims of added difficulties for trade deals, and more concerns about the weakness of the pound. One study, however, points out that the EU may have more to lose from Brexit than the U.K.

The stock market crash of 1987 was so surprising, big, and powerful that it left a permanent crater on the landscape of financial markets. This crater is most clearly visible when looking at a chart of implied volatilities for any normal stock or equity index. People almost always pay more for options that protect against a down-movement in a stock then they do for options that pay off in the event of the equivalent move up. That wasn't the case pre-1987, when hedges roughly cost the same amount in either direction. This changed shape of the curve is known as The Volatility Smile, and it's also the name of a new textbook from Emanuel Derman on how to price options. Derman, of course, is the author of My Life as a Quant, which described his career at the forefront of the marriage between theoretical physics and Wall Street. Now everybody knows that physicists can go to work on Wall Street, but when Derman arrived at Goldman Sachs in the mid-80s it was still a novel thing. Even if quantitative finance isn't your thing, you should check out the first chapter of his new book which is available for free online. It gives a really nice plain-English overview of what financial models are and what they seek to accomplish. And if you're still interested, you should check out Derman's appearance on What'd You Miss on BloombergTV this afternoon at 4:30 ET, where we'll talk about options pricing theory, math, and the current state of finance.