The cancellation of the bond sale is the company’s reaction to an anonymous whistleblower letter.

Mattel was made aware of the letter on the 6th of August, according to a filing, and decided to cancel the sale of senior notes due in 2027, in order to investigate the contents of the letter.

The announcement drove Mattel’s share price down as much as 11%, to $11.90, in after-hours trading.

The sale had been scheduled to close on Thursday. Mattel said it plans to refinance bonds that are due in October 2020 before maturity. Spokeswoman Dena Cook said the company had no comment to add beyond what’s in the filing, and did not disclose further details about the letter.

Mattel has about $3b of debt on its books, with about $250m due next year. The company had planned to refinance its 2020 obligation with the pulled bond.