I quote: "Transaction information - When you use Google Wallet to conduct a transaction, information regarding the transaction may be stored in the Google Wallet Application. We may collect information about these transactions from the Google Wallet Application. We also collect transaction data from your use of the Google Wallet Service. For example, if you use the Google Wallet Application to make a purchase at a merchant or download a merchant coupon, we may obtain information regarding that transaction from the Wallet Application, from the merchant and/or a partner, as applicable. The information may include the date and time of the purchase, the store location, the amount of the purchase, and the offer associated with the transaction. "
http://www.google.com/wallet/privacy.html
I quote: "Transaction information - When you use Google Wallet to conduct a transaction, information regarding the transaction may be stored in the Google Wallet Application. We may collect information about these transactions from the Google Wallet Application. We also collect transaction data from your use of the Google Wallet Service. For example, if you use the Google Wallet Application to make a purchase at a merchant or download a merchant coupon, we may obtain information regarding that transaction from the Wallet Application, from the merchant and/or a partner, as applicable. The information may include the date and time of the purchase, the store location, the amount of the purchase, and the offer associated with the transaction. "