1. Oil slides: Crude oil futures were sliding again by about 1.5% to trade around $48 per barrel.
Oil prices had been trading well above the $50 level for the past few months after oil cartel OPEC arranged for big producers to cut their output. But enthusiasm over the deal has waned.
"The rapidly diminishing optimism over the OPEC production cut deal has heavily dented buying sentiment towards oil," said Lukman Otunuga, a research analyst at FXTM.
Crude was trading around the $26 level early last year over concerns about an oversupply of oil in global markets.
2. Meek markets: There's also a distinct lack of optimism in global stock markets.
U.S. stock futures are pointing down.
Nearly all European markets declined in early trading. Asian markets ended the day with mixed results.
This comes after the Dow Jones industrial average, S&P 500 and Nasdaq all eked out minor gains for themselves over the course of last week. They're trading near their all-time highs set earlier this month.
On the flip side, gold prices have resumed their climb. The shiny metal has seen its price rise by 7% since the start of the year.
3. Stocks to watch -- Deutsche Bank; Vodafone: Shares in Deutsche Bank were hit after the company reported its full-year results.
Germany's biggest bank recently announced plans for a huge share sale worth $8.5 billion to help improve its financial health.
Shares in Vodafone were steady after the telecom giant announced it's joining forces with a top rival in India to create the country's largest cell phone carrier.
The U.K. telecom firm said Monday it's merging its Indian operations with those of Idea Cellular. The result will be a wireless operator with nearly 400 million customers -- roughly 75 million more than the entire population of the U.S.
4. Coming this week: Monday - Bill Gates meets with President Trump; CIA, NSA and FBI testify before the House Intelligence Committee about Russia's alleged role in meddling in the U.S. election Tuesday - U.K. releases inflation figures; General Mills, BMW and FedEx report earnings Wednesday - U.S. existing home sales report; Starbucks annual shareholder meeting Thursday - Accenture reports earnings; U.S. new home sales report Friday - Samsung annual shareholder meeting