Nvidia did not warn at least some major customers in advance about new U.S. export rules it was told about a week ago requiring it to obtain licenses to sell its China-focused artificial intelligence chip,

Nvidia Corp.’s shares were tumbling in after-hours trading Tuesday, after the chip giant disclosed in a regulatory filing that it expects to include charges of up to $5.5 billion in its fiscal first quarter related to licensing of its chips to the Chinese market.

The chip manufacturing giant, which has been at the heart of the AI boom, will require licences to export its H20 AI chip to China.