In the wee hours of Sunday night, Twitter's (NYSE:TWTR) Chief Executive Jack Dorsey made it official: Several top-level executives are leaving. Engineering chief Alex Roetter, product head Kevin Weil, human-resources vice president Skip Schipper and media head Katie Stanton are all jumping ship, while two new board members will be appointed this week to help the company through the turnaround. With shares of Twitter down around 55% in the past year (below the stock's IPO price), investors will be waiting to see if the major management shake-up will finally restore confidence. TWTR -5.9% premarket.

Economy

The U.S. eastern seaboard is still digging out from a weekend blizzard that knocked out power for several hundred thousand customers, grounded more than 13K flights, and shattered snowfall records in Washington and New York City. Although federal government offices in the Washington area will be shut today, a spokeswoman for the New York Stock Exchange said the market planned to open as usual.

Fund managers that were relaxed about slightly tighter monetary policy last month are wondering whether that was complacent, as concerns surface over whether they're now operating without the safety net they had grown attached to during the post-financial crisis. "It is reasonable for investors to wonder whether Fed's December rate hike was a policy error," admits Bob Michele, chief investment officer of JPMorgan Asset Management. The FOMC's January policy meeting begins tomorrow.

Former New York City Mayor Michael Bloomberg is seriously considering a run for president as an independent, and has asked aides to explore a potential bid. Sources say the unlikely success of Donald Trump, along with polls suggesting Hillary Clinton's campaign may be flagging, have driven him closer than ever to throwing his hat in the ring. Bloomberg has set a deadline for making a final decision in early March.

Puerto Rico's struggling power utility has reached a deal with some lenders that protects it from litigation through Feb. 12, but the agency's future remains uncertain after the collapse of a crucial restructuring plan over the weekend. Fixing PREPA is key to solving Puerto Rico's problems at large. Officials had pointed to the deal as a model for other restructuring negotiations as the island seeks relief from creditors who hold nearly $72B of its debt.

Russia's economy contracted the most since 2009 last year as the price of oil sank and sanctions over the conflict in Ukraine curbed access to international financing. According to preliminary estimates, gross domestic product fell 3.7% after growth of 0.6% in 2014. "The economy’s going through big adjustments - it's still addicted to oil," said Vladimir Miklashevsky, a strategist at Danske Bank A/S. "The weak ruble and import substitution will continue to support local production, although...it's a long journey to recovery."

Following the lifting of economic sanctions and the release of billions of dollars' worth of frozen Iranian assets, Tehran is ready for business: The country just struck a provisional deal to buy eight A380 superjumbos, while an agreement for 100 more Airbus (OTCPK:EADSY) jets could be completed this week. The Islamic Republic is also looking to purchase over 100 planes from Boeing (NYSE:BA) and regional aircraft from Bombardier (OTCQX:BDRAF, OTCQX:BDRBF), MRJ, Embraer (NYSE:ERJ) and Sukhoi. Insurers and reinsurers are exploring ways to tap the market worth $7.4B in premiums - Allianz (OTCQX:AZSEY), Zurich Insurance (OTCQX:ZURVY), Hannover Re (OTCPK:HVRRY) and RSA (OTCPK:RSNAY) are all currently evaluating potential opportunities. Over the weekend, China and Iran also mapped out a plan to broaden relations and expand bilateral trade up to $600B over the next decade.

Crude prices are turning lower again on oversupply woes and profit-taking, reversing from last week's surge on short-covering and fuel demand triggered by freezing weather in parts of the northern hemisphere. Over the weekend, Saudi Aramco said it would not reduce its new investment in oil and gas production capacity despite cost-cutting measures, and Iran marked its first sale of crude to a European country since the lifting of sanctions. Crude futures -3.1% to $31.19/bbl.

Stocks

This week's quarterly earnings announcements will include results from three of the tech sector's most important companies: Apple (NASDAQ:AAPL), Microsoft (NASDAQ:MSFT) and Amazon (NASDAQ:AMZN). Investors on Tuesday will try to divine from Apple's numbers the firm's future revenue streams, focusing specifically on iPhone sales. On Thursday, Microsoft and Amazon shareholders will want to see strong growth in both companies' computing services businesses.

Alphabet has agreed to pay £130M ($185M) in a back-tax settlement with U.K. authorities, setting off a hostile response from opposition politicians questioning the government's handling of the case. According to a panel in 2013, Google (GOOG, GOOGL) paid just $16M in U.K. corporation tax from 2006 to 2011 on $18B of revenue. Separately, Apple (AAPL) is facing a European tax investigation that could force the iPhone maker to pay more than $8B in back taxes.

VMware will announce it's laying off 900 workers (5% of its workforce) in the coming week, possibly in tandem with its Thursday Q4 report or a day before, sources told Bloomberg. The report comes with parent EMC set to be acquired by Dell, and with VMware shares having tumbled to their lowest levels since 2010 amid a market selloff. VMware (NYSE:VMW) slid as low as $46.33 on Wednesday, and closed Friday at $49.50.

Johnson Controls and Tyco International are in advanced talks to merge, in a deal that could value the latter as high as $20B and signal that companies are still willing to embark on large mergers despite the recent market volatility. Both firms have recently fallen on hard times - Johnson (NYSE:JCI) has dropped more than 20% over the past year, while Tyco (NYSE:TYC) is down more than 25%. Johnson Controls CEO Alex Molinaroli is expected to run the combined company.

Struggling with the fallout from plunging energy prices, SandRidge Energy (NYSE:SD) is exploring its debt restructuring options and has been in talks with investment banks and law firms about hiring advisors. Debtwire had reported on Jan. 13, that SandRidge - which produces oil and gas from shale formations in the Mid-Continent region of the U.S. - had hired Houlihan Lokey to craft a restructuring plan.

SunEdison is set to give hedge fund Greenlight Capital a board seat after a decline in the solar company's stock price and the departure of some senior officials. In October, billionaire David Einhorn told investors that the firm's "hard-to-decipher financial statements" were to blame for its decline. Greenlight owned about 8% of SunEdison (NYSE:SUNE) as of Jan. 11. SUNE +4.9% premarket.

Increasing its pace of development from last year, McDonald's (NYSE:MCD) plans to open more than 60 restaurants in Russia in 2016. "We have seen significant growth of our market share as we continued expansion," Khamzat Khasbulatov, chief executive of McDonald's Russia, told a news conference. He added that the company had to make "serious adjustments" to its business model after sanctions and the weakening of the ruble put pressure on its margins.

Siemens has agreed to buy CD-adapco, a privately held U.S. engineering software firm, for close to $1B in cash, Reuters reports. The acquisition comes ahead of Siemens' (OTCPK:SIEGY) annual shareholders meeting on Tuesday. Investors there intend to remind CEO Joe Kaeser that following several years of stagnation and restructuring, this year should be about delivering operational improvements and boosting profitability.

Samsung Electronics is considering all possible options to grow its home appliances division including mergers or acquisitions, a senior company official told reporters. Suh Byung-sam, head of Samsung (OTC:SSNLF) appliances, also said that Haier's acquisition of General Electric's (NYSE:GE) appliances unit would have no serious impact on its business in the near term.

Lawyers for Martin Shkreli have asked a federal judge for guidance on a demand stating he must appear at a hearing on Tuesday, writing that if travel restrictions on him are not lifted, the congressional subpoena should be blocked. The terms of Shkreli's $5M bail package don't allow him to travel. The former pharma executive previously said he plans to invoke his Fifth Amendment rights at the hearing, which will protect against self-incrimination.

U.S. health inspectors have found serious deficiencies at Theranos' northern California laboratory that, if not fixed, could see the lab suspended from the Medicare program, sources told WSJ. It wasn't immediately clear what regulators faulted the blood-testing firm for, but results of the inspection are expected to be made public soon. The findings could also lead Walgreens (NASDAQ:WBA) to take an even harder look at what remains of its partnership with Theranos.

Takata shares tumbled 10% in Tokyo overnight, hitting their lowest level since 2009, after U.S. regulators said recalls involving the company's air bags would expand by around 5M vehicles. Takata (OTCPK:TKTDY) executives are also meeting automakers this week to discuss the company's financial condition, including how to split recall-related costs that could climb into the billions of dollars.

San Francisco's largest taxi company, Yellow Cab Cooperative, has filed for bankruptcy protection, the latest in a string of traditional taxicab operators to turn to Chapter 11 amid the rapid rise of ride-hailing rivals like Uber (Private:UBER) and Lyft (Private:LYFT). Chicago's Yellow Cab taxi service filed for bankruptcy last year blaming its financial woes, while the price of New York's yellow cab medallions has plummeted from more than $1.3M in 2013 to between $700K-$800K.

Today's Markets

In Asia, Japan +0.9% to 17111. Hong Kong +1.4% to 19340. China +0.8% to 2936. India +0.2% to 24486.
In Europe, at midday, London flat. Paris flat. Frankfurt +0.1%.
Futures at 6:20, Dow -0.3%. S&P -0.2%. Nasdaq -0.3%. Crude -3.1% to $31.19. Gold +0.8% to $1104.80.
Ten-year Treasury Yield -2 bps 2.02%

Today's Economic Calendar

10:30 Dallas Fed Manufacturing Survey