Hi! Welcome to the Insider Advertising daily for September 21. I'm Lauren Johnson, a senior advertising reporter at Business Insider. Subscribe here to get this newsletter in your inbox every weekday. Send me feedback or tips at ljohnson@businessinsider.com.Today's news: Instagram eyes big push into messaging with API, Oracle becomes a minority investor in TikTok, and how big brands are taking marketing in-house. Instagram chief Adam Mosseri Justin Sullivan/Getty Images Instagram is building a messaging API to help brands manage their DMs with usersInstagram is building an API for its messaging service that will help brands manage their conversations with users, reports Rob Price.In theory, the feature will let large brands access their messages through third-party services similar to features that already exist in Messenger and WhatsApp.Currently, brands have three options for managing their DMs with Instagram users.