US stocks sink further with S&P 500 on course for worst week since December

• US stocks opened lower on Friday to cap off a volatile week. 
• The S&P 500 is on course for its worst week since December. 
• OIl prices jumped as Russia cut production over sanctions. 

US stocks opened lower on Friday, with major indices set to cap off a volatile week with more losses. 

The S&P 500 was on course for its worst week since December, and investors are seeking cover after a string of disappointing earnings reports. Shares of ride sharing company Lyft sank more than 30% after an earnings miss. 

Elsewhere, Russia said it will cut oil production by 500,000 barrels a day, beginning in March, in response to a Western price cap effort. 

Here's where US indexes stood at the 9:30 a.m. ET open on Friday:

• S&P 500: 4,074.34, down 0.18%
• Dow Jones Industrial Average: 33,681.51, down 0.05% (18.37 points)
• Nasdaq Composite: 11,733.29, down 0.48%

Here's what else is happening this morning:

• Ed Yardeni says the central bank should "chill" with rate hikes on encouraging inflation data. 
• Insider compiled a list of the 10-best S&P 500 performers so far this year. 
• Buy more Tesla stock to get in on the artificial intelligence craze, Cathie Wood said. 

Crypto firm Kraken will stop staking tokens and pay a $30 million fine. 

In commodities, bonds and crypto:

• West Texas Intermediate crude oil climbed 0.96% to $78.75 per barrel. Brent crude, oil's international benchmark, gained 1.38% to $85.61. 
• Gold ticked up 0.32% to $1,8767.48 per ounce.
• The yield on the 10-year Treasury was relatively flat at 3.684%. 
• Bitcoin added 0.05% to $21,826.37.