What will happen if I make large budget changes to a portfolio?

Typically, you should not change the budget by more than 25% to allow the optimization capability to learn gradually. However, when it is necessary to make significant budget changes, we recommend that you let AdLens determine the optimal bids by enabling the Portfolio's spend management option to auto adjust campaign budget limits.
 
In any case, you should expect to see volatility and possibly some overspending in the first few days after a large budget change, especially when the historical spend is much lower or higher than the new budget, as any keywords are bid to their previous positions. As soon as AdLens has new data on these positions and is able to create better forecasts, the bidding technology will adjust and the portfolio will stabilize.