A Sears Holdings Corp investor on Thursday asked the struggling retailer to consider options including going private and investigate what it called an "unusually high volume" of short selling in the company's shares.

Switzerland-based Memento SA also called for a temporary suspension of short selling in Sears' shares.

Memento is the investment manager for the Elarof Trust, which is owned by the Swiss-based Spadone family and owns nearly two million Sears shares.