This supplementary product ensures that, in the event of a one-time claim (in some cases also repeated claims), your bonus level is not raised and therefore your premium is not increased in the insurance year that follows. Most insurance companies offer bonus protection as a supplementary product for liability and comprehensive and collision insurance (casco). The products offered by the individual insurance providers vary considerably. Further information on the systems of car insurance products with or without bonus protection can be found here.
Bonus protection is not exactly cheap, particularly as it is usually based on your bonus level. In other words, the higher your current bonus level, the more expensive your bonus protection will be. This is why many people choose not to take out bonus protection insurance – their premiums are already expensive enough because they are on a higher bonus level. However, this decision may backfire if you have to make a claim. When you make a claim, you also have to pay a deductible, plus your insurance premiums go up – all of which is pretty frustrating.
Nevertheless, if you do make a claim, and don’t have bonus protection, and you're already on a high bonus level, it’s not the end of the world. You can cancel your insurance policy when it expires after a year (for annual policies) or if you make a claim (up to two to four weeks after the insurance company has notified you that the insurance has covered or will cover the damage). A new insurance company will not usually penalize you in terms of bonus level just because you made a claim. But a word of warning: before you cancel, it’s a good idea to use the premium calculator at comparis.ch to check what other insurance deals are available to you and under what conditions.