In Microsoft Advertising, you can have each campaign use an individual budget or you can have multiple campaigns use a single shared budget. With a shared budget, Microsoft Advertising automatically adjusts how your budget is spent across its campaigns to help you improve your ROI. Here's how it works:
Let's say you want to spend $40 per day on Campaign A and $40 per day on Campaign B. One day, Campaign A gets fewer clicks than usual, and only spends $30. Meanwhile, demand for ads from Campaign B is higher than usual. With individual budgets, Campaign B could run out of funds, leaving potential clicks on the table. But with a shared budget, Microsoft Advertising reallocates the $10 Campaign A didn't need to Campaign B, letting it capitalize on the additional demand.
You can always go back to using individual budgets for complete control over how much you spend on each campaign.
Once you have set up at least one shared budget, when you create a new campaign, you will have the option to choose a shared budget for it to use.
When you go back to your Shared Library and click View Budgets again, the shared budgets you created will appear in the table. Here, you can keep track of each shared budget's performance. If a shared budget has run out of funds for the day, its status will appear as Budget paused. You can also click the budget in the table to see how the budget is spent across the different campaigns that use it.