Occidental Petroleum Corp (NYSE: OXY) is up 4.0% today following news that Warren Buffett increased his stake further in the oil producer this week.

The legendary investor bought more than 10 million shares of the Houston-headquartered firm for $588 million across multiple transactions in recent days.

Buffett now owns about 27% of Occidental Petroleum, as per a filing with the Securities & Exchange Commission on Thursday. His conglomerate Berkshire Hathaway also has warrants to buy another 83.8 million shares of the New York listed firm.

The “Oracle of Omaha” opting to purchase more shares of Occidental Petroleum signals his confidence in the $12 billion acquisition of CrownRock that the oil giant announced on Monday (read more).

$OXY is currently down over 10% versus its year-to-date high.

It is worth mentioning here, though, that Roger Read – a Wells Fargo analyst reads the aforementioned transaction differently.

Read maintained his “hold” rating on Occidental Petroleum this week as the CrownRock deal is coupled with a material increase in leverage. That’s because the hydrocarbon exploration company plans on issuing $1.7 billion in stock and $9.1 billion in debt to finance the said acquisition.

Occidental Petroleum will have to divest up to $6.0 billion worth of assets to manage this leverage, which, as per the Wells Fargo analyst, creates financial uncertainty that may hurt the momentum in $OXY.