U.S. regulators are set to release a long-awaited rule requiring companies to tell shareholders how much top executives earn relative to the performance of their shares.

The new yardstick may include only part of executives’ compensation. It excludes unvested stock grants and options that can form the biggest chunk of pay years down the road, according to two people familiar with the matter, who asked not to be named because the proposal hasn’t been made public.

The Securities and Exchange Commission has struggled for five years to issue the pay-for-performance provision, which was mandated in the 2010 Dodd-Frank Act amid public outrage over executive payouts that were awarded even as stocks tanked. Many companies have pushed for the narrower formula for defining compensation that paints a more modest picture of how much top executives are paid.

The plan would require companies to report in their proxy statements the trend in executive pay over several years, while also showing charts and possibly a narrative that lays out how the compensation compares with investment returns. Proxies are sent out ahead of company’s annual meetings, where shareholders get to vote on directors and weigh in on pay.

The SEC’s proposal hews closely to models used by companies such as General Electric Co., Exxon Mobil Corp. and the Coca-Cola Co., which for years have given investors supplemental disclosures with pay totals that strip out unvested stock and options as well as changes in pension value.