Snapchat is set to come under further pressure next week when investors are allowed to sell shares for the first time since it went public in March.

The “lock-up” period that bars shareholders from cashing in on their stakes expires next Saturday, 150 days after the company’s initial public offering.

It means they will be able to sell shares on the next trading day, Monday July 31.

Shares in Snap Inc, the photo messaging app’s parent company, have fallen below their $17 (£13.10) flotation price in recent weeks following a disappointing set of maiden results and fierce competition from Facebook.

The lossmaking company is facing questions about whether it can continue to attract users as Facebook-owned Instagram clones many of the features that have made it a success. It is under pressure to live up to the $24bn (£18.5bn) valuation it floated at in March, which came despite it being unlikely to turn a profit this decade.