Emails claiming to be from a hotel about a wrong transaction on your credit card are being sent worldwide with the intention of infecting your computer with a malware. In this case it claims to come from the booking department of the Hotel Swissotel in Chicago: “We are sorry to inform you that on July 26th, 2011 Hotel transaction transaction for an overall amount of $1857. Please see the attached form. You need to fill it in and contact your bank for the return of funds””]
Source: https://grahamcluley.com/hotel-credit-card-wrong-transaction-email-malware-attack/