The company said that the sale of an additional 450 million shares took place during the initial public offering process.

The oil and gas company, which is majority owned by the state, began publicly trading on the local Saudi Tadawul exchange on Dec. 11. It hit upwards of $10 a share on the second day of trading. This gave Aramco a market capitalization of $2 trillion, making it comfortably the world's most valuable company.

Aramco's additional sales mean the company has publicly floated 1.7% of its shares. It's IPO, even before the added sales, was the world's largest ever.

The shares sold in the over-allotment option "had been allocated to investors during the bookbuilding process and therefore, no additional shares are being offered into the market today," Aramco said.

Company shares traded down Sunday, dipping to around 34.7 riyals, or $9.25 a share, amid heightened tensions in the Persian Gulf between Iran and the United States. Aramco was a target of rising tensions over the summer when a missile and drone attack, which Saudi Arabia and the U.S. blame on Iran, temporarily halved its production.

Sunday's trading figures value Aramco at $1.85 trillion, still well ahead of Apple, the second largest company in the world after Aramco, but below the $2 trillion mark sought by Crown Prince Mohammed bin Salman.