Mortgage company not adjusting HELOC rate with prime rate

[Jim D.]

I have a HELOC with an adjustable rate, which the terms clearly state is pegged to the prime rate plus 1.99%. I noticed they were quick to increase the rate when the prime rate was going up, but they have not reduced it since the prime rate started going down in 2019. This is a big difference! And yes, shame on me for not seeing this sooner...was only prompted to check after the biggest rate cuts last month.

So, how long does a mortgage company have to adjust the rate?  Can they simply change these terms at their discretion?  I assume "no" but I can clearly see they are not adjusting for the prime rate decreases.  And I can call them but I know the wait time will be very long (and I want to be prepared in advance).

Finally, is this a typical approach to HELOC rates (i.e. prime + 1.99%), or are better rates available?