Appearing in federal court in Manhattan, Ingrid Lederhaas-Okun admitted she had stashed the jewelry in her home in Darien, Conn., where she was arrested earlier this month.
"I knew it was illegal to steal, and I did so regardless. ... I'm very sorry," the 46-year-old told a judge before pleading guilty to one count of interstate transportation of stolen property.
As vice president of product development, Lederhaas-Okun had authority to check out jewelry from Tiffany to provide to potential manufacturers to determine production costs. Authorities alleged that after she left Tiffany in February, the company discovered she had checked out 164 items that were never returned.
The items included numerous diamond bracelets in 18-carat gold, diamond drop and hoop earrings in platinum or 18-carat gold, diamond rings in platinum, rings with precious stones in 18-carat gold, and platinum and diamond pendants.
When confronted about the missing jewelry, Lederhaas-Okun claimed that she had left some of it behind at Tiffany and that some had been lost or damaged, according to a criminal complaint. But an investigation found that Lederhaas-Okun resold some of the goods to an unidentified international dealer for more than $1.3 million. Other items were found in her home.
Bank records showed that since January 2011, the dealer wrote 75 checks to her or her husband for amounts of up to $47,400, the complaint said. Investigators also recovered purchase forms signed by Lederhaas-Okun that said the items were her personal property.
Authorities alleged Lederhaas-Okun purposely checked out items valued at under $10,000 apiece to avoid detection. The company takes a daily inventory of all checked-out items worth more than $25,000.
Lederhaas-Okun faces a maximum of nearly four years in prison at sentencing on Dec. 10.