Benesse Holdings Inc. has withdrawn its earnings forecast for the year because it can’t determine how the theft of its customer data will impact its correspondence education subsidiary.

The company said Thursday it booked ¥26 billion as a special loss for the April-June quarter related to the massive theft of client data from Benesse Corp., its main subsidiary.

It also withdrew its earnings forecast for the year to March 2015 because it cannot tell how the incident will affect the subsidiary, known as Japan’s leading correspondence education provider for children.

Vice Chairman Tamotsu Fukushima and another executive resigned Thursday to take responsibility for the theft, which was carried out by a system engineer hired as a contract worker by a subsidiary who got access to Benesse’s database. The man was recently arrested on suspicion of stealing some of the data.

The special loss forced Benesse Holdings to incur a group net loss of ¥13.64 billion in the quarter against a year-earlier profit of ¥2.63 billion, while consolidated sales rose 2.2 percent from a year earlier to ¥115.52 billion.

The loss covers costs for apology gifts to customers, information security and other measures regarding the leak.