He was hit with additional fraud charges in California for that alleged scheme.
Sadleir opened a bank account for a fake company and transferred $25 million of BlackRock's investment that he'd claimed would be used for advertising, Department of Justice authorities said.
An affidavit in the case notes that Aviron Group, Aviron Licensing and Aviron Releasing, the companies for which Sadleir sought the loans, are "not engaged in any ongoing operations", prosecutors said.
A lawyer for Sadleir could not be reached.
Officials from multiple federal agencies involved in the investigation condemned what they said was Sadleir's misuse of a program meant to help people, at a time when many employees in the film and other industries are in need of assistance.
The PPP was meant "to help small businesses stay afloat during the financial crisis, and we will act swiftly against those who abuse the program for their own personal gain", U.S. Attorney Nick Hanna in Los Angeles said in a statement.
Sadleir used a large portion of that sum as his personal piggy bank, spending almost $14 million of it on an estate in Beverley Hills, prosecutors charged.
The BlackRock fund had $574 million of assets as of May 21, and normally invests most assets in debt and loans.
Aviron, which Sadleir founded in 2017, released films such as "Kidnap" with Halle Berry; "Destination Wedding" with Winona Ryder and Keanu Reeves; "A Private War" with Rosamund Pike; "Serenity" with Matthew McConaghey and Ann Hathaway; and the teen romantic drama "After'". It sued Sadleir for fraud in a NY state court in December.
To keep up the ruse, FBI Asst. Director William F. Sweeney Jr. said Sadleir "allegedly even went so far as to pose as a female employee of the sham New York-based company he created to further his illegal activity". He's accused of engaging in two fraudulent schemes related to a $75 million investment that BlackRock Multi-Sector Income Trust made in Aviron. In a separate case, the Securities and Exchange Commission also accuses Sadleir of violating antifraud provisions of securities laws.
Sadleir faces up to 124 years in prison if convicted on all charges.
He then "used the misappropriated money to support his lavish lifestyle, including cash withdrawals and the purchases of a luxury auto and a mansion in Beverly Hills", the lawsuit said.