Investor Carl Icahn increases his stake in Occidental Petroleum

• Now he's taking advantage of macro conditions (coronavirus, Saudi-Russia deal collapse, etc.) to strengthen his hand, as Occidental's market cap has fallen to $10.5 billion and it just slashed its dividend for the first time in 30 years.

Icahn wants control, which would include a new CEO and a new board of directors.

• The bottom line: "Many shale producers including Occidental were struggling to turn a profit even before the coronavirus and tension among big oil-producing states sent crude prices down sharply. Occidental is particularly vulnerable given its high debt level — roughly $40 billion at last count," writes the Wall Street Journal.

Go deeper: What the oil market's collapse means for the climate