WhatsApp currently shares certain categories of information with Facebook Companies.

“We may use the information we receive from them, and they may use the information we share with them, to help operate, provide, improve, understand, customize, support, and market our Services and their offerings, including the Facebook Company Products,” says WhatsApp.

"The information we share with the other Facebook Companies includes your account registration information (such as your phone number), transaction data, service-related information, information on how you interact with others (including businesses) when using our Services, mobile device information, your IP address, and may include other information identified in the Privacy Policy section entitled ‘Information We Collect’ or obtained upon notice to you or based on your consent," it adds.
 https://www.techradar.com/news/whatsapps-new-privacy-policy-requires-you-to-share-data-with-facebook 

 Yeah. That was actually when I stopped using WhatsApp.