Stocks closed in the red to end a week that saw more shaky headlines out of Greece. Crude oil and the dollar also edged lower on Friday. First, the scoreboard: Dow: 17,898.84, -140.53, (-0.78%) S&P 500: 2,094.11, -14.75, (-0.70%) Nasdaq: 5,051.10, -31.41, (-0.62%) And now, the top stories on Friday: Twitter shares halted a rally that began in after-hours trading on Thursday when the company announced CEO Dick Costolo is stepping down. The stock surged more than 7% after the close, and opened about 3% higher in early trading. But just after 1 p.m., the stock went red, although it gained by about 0.5% in the final hour of trading. Wall Street isn't so sure about Jack Dorsey, Twitter's interim CEO from July 1. In research notes on Friday, several analysts expressed concern that the company may continue to underperform. However, there were no big changes to their price targets or stock ratings. Macquarie analysts wrote, "the surprise timing of this announcement, combined with the "steady-as-she-goes" tone of the executives on the conference call, indicate to us that TWTR will continue to underperform until it can either a) significantly improve its execution against its current strategy, or b) institute a new vision." Business Insider's Henry Blodget notes that the whole plan for an "interim CEO" is pretty much a sham. There's a 'Plan B' for Greece. According to Reuters, senior EU officials formally discussed, for the first time, the possibility that Greece will default on its debt. This follows the IMF's abandonment of talks with Greek officials on Thursday. "The discussion was very theoretical because the scenario of a eurozone country defaulting within the currency union would be without precedent," Reuters reported. The US oil rig count fell for a 27th straight week. Data from driller Baker Hughes showed that the number of active US oil rigs fell by seven to 635 this week, the lowest count since August 6, 2010. The combined count fell by nine to 859. West Texas Intermediate crude oil was lower for much of Friday, dipping to as low as $59.75 per barrel. US oil production continues to surge, although the Energy Information Administration forecasts a slowdown from June until next February. In economic data, the preliminary reading of the University of Michigan's consumer sentiment index for June jumped to 94.6, crushing the forecast for 91.2. In the release, the index's chief economist Richard Curtin wrote, "The June gain was due to the most favorable personal financial prospects since 2007, with households expecting the largest wage gains since 2008." Producer prices posted the biggest month-over-month gain since 2012 in May. The Producer Price Index rose 0.5% month-over-month and fell 1.1% year-over-year. Excluding food and energy, core PPI rose 0.1% and 0.6% respectively. A 15.6% spike in fuel prices accounted for three-quarters of the increase. Chicken wings chain Wingstop surged 60% in its public market debut. The company had priced its shares at $19, higher than the previously indicated range of between $16 and $18 a share. The stock rose to as high as $31 per share, valuing the company at around $880 million. Wingstop had $8.9 million in profits last year, according to its IPO filing. As at December 2014, it reported 712 restaurants across 36 states and six countries. Wingstop joins Bojangles, El Pollo Loco, and Shake Shack among restaurant chains that have gone public in the past year. Shares of for-profit college ITT Educational spiked 30% following a quarterly earnings report filed one month late. The company is struggling financially and is under investigation for fraud charges by the SEC; it allegedly hid the poor performance and financial impact of two student loan programs from its auditor. Earnings jumped to $10.4 million, or 44 cents a share in the quarter – reflecting lower expenses. "This is the dumbest rumor ever," wrote hedge fund manager Whitney Tilson on chatter that Home Depot seeks to acquire Lumber Liquidators, whose shares jumped 12%. The hardwood flooring retailer is under federal investigation, following allegations that its flooring sourced in China contains excessive levels of formaldehyde. Tilson wrote, in an email, that Lumber Liquidators may only be an acquisition target two years from now, when the legal liabilities have faded. The company declined comment. DON'T MISS: One of corporate America's most controversial practices could become a major issue in the 2016 election »Join the conversation about this story » NOW WATCH: Forget the Apple Watch — here's the new watch everyone on Wall Street wants