 In 2014, there were 1,469 oil and gas firms listed on stock exchanges around the world, with a combined market capitalization of US$4.65 trillion.In 2019, Saudi Aramco was listed and it touched a US$2 trillion valuation on its second day of trading, after the world's largest initial public offering.Air pollution from fossil fuels in 2018 has been estimated to cost US$2.9 trillion, or 3.3% of global GDP.