By Anora M. Gaudiano and Sara Sjolin, MarketWatch

Tesla rises after electric big rig unveiled

U.S. stocks fell slightly on Friday, with the modest losses on track to erase weekly gains for the S&P 500 and Dow industrials. The Nasdaq Composite was still looking to post a modest weekly gain, however.

Some analysts said the expiration of options on Friday may be creating a little bit of volatility.

What are the main benchmarks doing?

The S&P 500 was off 4 points, or 0.2%, to 2,581, with seven of the 11 main sectors trading lower. The benchmark index is on track to end the week unchanged.

The Dow Jones Industrial Average slipped 85 points, or 0.4%, to 23,373 and looking at a small weekly loss, which would be the second in a row.

The Nasdaq Composite Index was off by 2 points at 6,790, but on track to post a 0.6% gain over the week.

What are driving the markets?

Investors continued to track developments surrounding the Republican tax cut plan in Washington. The focus is now on the Senate, after the House of Representatives passed a sweeping bill to overhaul the tax code (http://www.marketwatch.com/story/house-passes-tax-overhaul-as-spotlight-turns-to-senate-2017-11-16) on Thursday.

See:Here are the winners and losers of the tax plan the House just passed (http://www.marketwatch.com/story/here-are-the-winners-and-losers-of-the-tax-plan-by-income-bracket-2017-11-03)

But the Republicans' proposed legislation has several steps to go, which analysts say could make the final tax deal very different from what it currently looks like.

The latest developments in the Russia probe were also seen as occupying investors' thoughts.

Special Counsel Robert Mueller's team issued a subpoena (http://www.marketwatch.com/story/mueller-subpoenaed-trump-campaign-documents-in-october-2017-11-16) to more than a dozen officials from Donald Trump's campaign in mid-October, asking them to hand over Russia-related documents, according to a report in The Wall Street Journal. Mueller is overseeing an investigation into whether Trump associates colluded with Russia to meddle in the 2016 presidential election. Both Moscow and Trump have denied any interference.

What are strategists saying?

"Obviously [on Thursday] the equity markets embraced 'the cup is only half full' adage, implying that tax reform is a fait accompli. Yet our contacts in the Senate suggest this may not be the case. If so, this sets the equity markets up for a letdown, despite the recent upside momentum," said Jeff Saut, chief investment strategist at Raymond James.

"The news about the subpoena overshadowed the first legislative triumph for President Donald Trump as Republicans pushed a $1.5 trillion tax overhaul through the House on Thursday. But obstacles remain in the Senate, which is refining its own version of the legislation amid objections from key GOP senators," said analysts at FxPro, in a note.

Which stocks are in focus?

Shares of Tesla Inc.(TSLA) rose 1.9% after electric-vehicle company Thursday night launched a semiautonomous electric big rig (http://www.marketwatch.com/story/tesla-unveils-sleek-electric-big-rig-with-500-mile-range-2017-11-17), which chief executive Elon Musk promised will deliver huge cost efficiencies. Tesla also added a surprise to the event on Thursday, unveiling a new version of the Roadster (http://www.marketwatch.com/story/elon-musks-fast-route-to-more-cash-a-new-tesla-roadster-2017-11-17).

Trucking company J.B. Hunt Transport Services Inc.(JBHT) said Friday it has made reservations to buy "multiple" Tesla Semi trucks (http://www.marketwatch.com/story/teslas-stock-gets-a-premarket-boost-after-jb-hunt-reseves-multiple-new-semi-trucks-2017-11-17). J.B. Hunt shares were off 0.8%.

21st Century Fox Inc.(FOX) rose 7.4% after reports Comcast Corp.(CMCSA) and Verizon Communications Inc.(VZ) are exploring bids to buy a big chunk of (http://www.marketwatch.com/story/comcast-seeks-to-buy-significant-part-of-fox-verizon-interested-too-2017-11-16) the Rupert Murdoch-built media empire. Comcast shares fell 1.8%, while Verizon was up 1.3%.

Hibbett Sports Inc.(HIBB) soared 15% as sports retailer blew past estimates for its fiscal third quarter and raised guidance for the full year (http://www.marketwatch.com/story/hibbett-sports-shares-jump-7-premarket-after-earnings-blow-past-estimates-2017-11-17).

Foot Locker Inc.(FL) jumped 23% after the athletic footwear retailer reported fiscal third-quarter profit and sales that fell less than expected (http://www.marketwatch.com/story/foot-lockers-stock-soars-after-profit-revenue-and-same-store-sales-beat-expectations-2017-11-17).

Electronic Arts Inc. shares(EA) fell 2.7% after the company late Thursday said suspended micropayments (http://www.marketwatch.com/story/ea-suspends-in-game-payments-for-new-star-wars-battlefront-ii-video-game-2017-11-16) on its highly anticipated new videogame "Star Wars: Battlefront II."

SailPoint Technologies Holdings Inc.(SAIL) soared 18% on its debut trading. The company late Thursday priced its initial public offering at $12 a share.

What economic data are expected?

October housing starts surged (http://www.marketwatch.com/story/housing-starts-booms-137-in-october-2017-11-17), rising 13.7% to a seasonally adjusted annual rate of 1.29 million. September estimate was revised to 1.135 million.

What are other markets doing?

Asian stocks closed mixed, while Europe markets were trading mostly lower (http://www.marketwatch.com/story/european-stocks-stumble-on-company-news-broker-downgrades-2017-11-17).

Oil prices rallied (http://www.marketwatch.com/story/oil-prices-rally-15-rebounding-from-2-week-low-2017-11-17), with crude up 2.1% at $56.50 a barrel as it rebounded from a two-week settlement low reached on Thursday.

Gold futures (http://www.marketwatch.com/story/gold-clings-to-weekly-gain-as-dollar-pulls-back-2017-11-17) rose 0.9% to $1,289.40 an ounce, getting a boost from the weaker dollar.

The ICE Dollar Index (http://www.marketwatch.com/story/dollar-slips-on-concerns-russia-probe-is-moving-closer-to-trump-2017-11-17) was 0.2% lower at 93.703 on Friday morning. Meanwhile, the yield on the 10-year Treasury (http://www.marketwatch.com/story/treasury-yields-slightly-higher-ahead-of-housing-starts-data-2017-11-17)note fell 4 basis points to 2.34%.

Bitcoin jumped to a fresh all-time high early Friday to touch $7,998.40, according to CoinDesk. The cryptocurrency has since pared back to trade around $7,870.69.

(END) Dow Jones Newswires

November 17, 2017 11:58 ET (16:58 GMT)