Exxon Mobil Corp. faces a May 29 vote on a shareholder resolution demanding more transparency in corporate political spending, especially on trade associations and “dark” money groups.

The resolution would require Exxon to compile and post on its website a semiannual report on its corporate political contributions and expenditures, both direct and indirect. It also would have to post company policies related to political spending. Activists want to know how much Exxon is spending, for example, to fight climate change regulations.