Tracking Competitor Ad Spend

Hi everyone.

We are moving into a new market (The US) and are trying to understand our competitors on Amazon US.

Did a full background check on some of our main competitors in this market and have found a lot of them to be owned by huge venture capitalist firms. One particular competitor grew 400% YoY

We want to try and understand what our competitors are spending on PPC per month. There’s no point in us trying to go head to head with a lion if we are just a mere house cat you know?

The only thing I can think off is try and identify keywords our competitors would spend on and then measure the change in the suggested bid? Even then, this at best would just show me the change in ad spend and not a full amount.

Anyone any ideas on this? Any advice

Thank you