Written by Billy Duberstein for The Motley Fool -> Shares of oil and gas services firm Halliburton (NYSE: HAL) rallied as much as 4.7% on Friday, before settling into a 3.4% gain as of 12:30 p.m. ET.

Conversely, falling oil prices can squeeze profitability, particularly for higher-cost producers. Moreover, oil prices influence investment decisions across the oil and gas value chain.

For years, as oil and gas companies increased production, they hired lots of workers, enriching communities across the United States. That is no longer true. The country is pumping more oil than ...

Shares of oil and gas services firm Halliburton (HAL 0.13%) rallied as much as 4.7% on Friday, before settling into a 3.4% gain as of 12:30 p.m. ET. Halliburton is the third-largest oilfield ...