8 German Bund yields, the benchmark for the euro zone, remained anchored around -0.51% on Monday, tracking US Treasury yields that also remained unchanged.
Traders believe that the reasons for the jump in the shares are short-sellers quickly buying back into the stock to cover potential losses, defined as a short-squeeze.
The trading strategy is high risk in that losses are theoretically unlimited when the stock rises instead of falling.
The Journal report, citing unnamed sources, said the Securities & Exchange Commission probe focused on unrealistic assumptions for highest-producing US oil field.
An unrealistic outlook could mislead investors and artificially boost a company's share price.
The Dow Jones Industrial Average rose 21.0 points, or 0.07%, at the open to 30627.47 and the S&P 500 rose 8.5 points, or 0.23%, at the open to 3764.61.
The Nasdaq Composite rose 70.2 points, or 0.54%, to 12958.522 at the opening bell.
Online trading platforms have reported a retail rush since the COVID-19 pandemic hit markets in March, with near-zero interest rates and a roaring rebound luring a new generation of stuck-at-home traders wanting to sharpen their skills on stocks.