Aviva, Barclays, Atos and five other firms have agreed to promote over-50s employment by publishing data about the age of their workforce.
They are responding to a call from the government’s Business Champion for Older Workers, Andy Briggs.
In February, he asked firms to increase older worker numbers by 12% by 2022.
Mr Briggs warned that by then, there will be 14.5 million more jobs, but only seven million younger workers entering the workplace.
He said older workers were vital in filling the UK’s “colossal skills gap”.
Mr Briggs, who is also chief executive of Aviva UK Life, wants more companies to commit to his pledge and publish data about the age of their workforce to help ensure his target of one million more older workers by 2022.
“Businesses can show leadership here, through committing to real change and actively seeking to recruit more over-50s into their organisations,” he said.
“By being open about the progress they are making, they can also lead the way in demonstrating the benefits of having a diverse team of employees that represents all sections of society.”
The eight companies that have signed up are: Aviva, Atos, Barclays, the Co-operative Group, Home Instead Senior Care, the Financial Services Compensation Scheme (FSCS), Mercer and Walgreens Boots Alliance.
In the newly published data, the figures for Atos show 33% of its workforce are between 50 and 64. Aviva employ 18.3% in this age group, Barclays 17% and the Co-op Group 26%.
While it is still uncertain what sort of agreement the next government will strike with the EU over freedom of movement, many employers are concerned about filling skilled and non-skilled jobs after Brexit.
Mr Briggs said the average age in the UK is now 40, 10 years older than it was in 1974.
By 2030, it is estimated half of all adults in the UK will be over 50.