Legal Question in Personal Injury in Texas

It isn't based on a certain percentage, the amount you must repay is usually defined by the insurance contract itself. Most contracts provide that you must reimburse 100% of the medical expenses they pay on your behalf. However, your attorney may be able to negotiate that amount down depending on the type of policy and the subrogation language in it.

I wrote an article on the topic of insurance subrogation in Texas that you can find here:

http://www.simmonsandfletcher.com/blog/general-questions-about-claims/pay-health-insurance-carrier-settlement/