Hey Hamza, A perfect example of a company for this question would be Nestle. Nestle is a very controversial company, particularly because of the environmental damages that they have caused. Their aggressive marketing of baby formula, slave labor, water bottling operations and many other issues have been an absolute PR nightmare for the company. Nestle boycotting has been ongoing for years, a recent impact was that they switched the labels on their water product in the US, they have removed the name Nestle from their Nestle Pure Life water, simply because of their completely tarnished reputation. People are not buying their products if they associate it with Nestle. This boycotting has for sure had a financial impact on the company, I could not find a source to cite for an exact numerical value, but if you dig online you might be able to put a number to their loss of revenue as a result of boycotting.