San Juan, Puerto Rico, June 10, 2021 – LUMA, operator of Puerto Rico’s electric power transmission and
distribution system since June 1, 2021, has become aware of a targeted Distributed Denial of Service
(DDoS) attack to the Mi LUMA customer portal and mobile application. A DDoS attack is an attempt to
make an online service unavailable by overwhelming it with traffic from multiple sources. The DDoS
attack was identified and has been issuing 2 million hits per second. As a result, many customers may
have had difficulty accessing information related to their account.

The attack has been reported to pertinent authorities and LUMA awaits the results of an ongoing
investigation.

LUMA regrets that its customers had to experience the inconvenience the attack may have caused and
looks forward to continuing to provide them with an exceptional customer service experience.

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