Exxon Mobil Corp reported a 28% year-on-year decrease in first-quarter profits to $2.06 per share, missing analysts' estimates by 13 cents despite significant gains in its Guyana operations. The decline in profits was attributed to weaker refining margins and lower natural gas prices, alongside a series of non-cash charges. This downturn occurred even as the company experienced surging oil output from its major development in Guyana.