Tupperware Brands is preparing to file for bankruptcy as soon as this week, Bloomberg News reported on Monday, citing people with knowledge of the plans.

The company's shares were down 15.8% at 43 cents after the bell. They closed down 57%.

Founded in 1946 by chemist Earl Tupper, the company's popularity exploded in the 1950s as women of the post-war generation held "Tupperware parties" at their homes to sell food storage containers as they sought empowerment and independence.

The COVID-19 pandemic provided a boost in sales from families who sheltered at home, cooked more and produced lots of leftovers. Sales have declined in recent quarters as the world re-opened.

Tupperware is planning to enter court protection after it breached the terms of its debt and enlisted legal and financial advisers, Bloomberg News reported on Monday.

The bankruptcy preparations follow protracted negotiations between Tupperware and its lenders over how to manage more than $700 million in debt, according to the report.

Tupperware did not immediately respond to a Reuters request for comment.

In March, the company warned it was not certain its business could continue as a going concern and faced a liquidity crunch. (Reporting by Juveria Tabassum; Editing by Shounak Dasgupta)