John Lewis is looking to dilute its partnership model by selling a stake to an external investor.

Chairwoman Dame Sharon White is said to be exploring an equity investment in the department store and Waitrose supermarket chain to raise up to £2 billion.

If it pursues the plan it would mean changing its partnership constitution which has underpinned the group since 1950, in which staff are given a share of profits in an annual bonus. However, the bonus has been held for only the second time as a result of a downturn in sales.

John Lewis has been held up as an example of “stakeholder capitalism”, but a combination of online sales and stronger competition from discount supermarkets and Marks & Spencer have put pressure on its bottom line.

The partnership last week announced a £230m loss and said 4,000 jobs will be lost.

Dame Sharon has attempted to revive the group’s fortunes by diversifying its activities into such sectors as housing.