In the sentence you provided, "P&G's" is a possessive noun. It shows ownership or association with P&G, which is Procter & Gamble. So, the complete phrase "P&G's" indicates something that belongs to or is associated with Procter & Gamble. Therefore, in this context, when you go to the supermarket and purchase toothpaste produced by Procter & Gamble, you are an example of P&G's customers or consumers.