trustee as hypothetical lien creditor

the rights of creditors—whether they are existing or hypothetical—to which the trustee succeeds are to be ascertained as of 'the date of bankruptcy,' not at an anterior point of time. That is to say, the trustee acquires the status of a creditor as of the time when the petition in bankruptcy is filed.

Defined by the Supreme Court in - Lewis v. Manufacturers National Bank of Detroit, 364 U.S. 603 (1961).