Back in the mid 90s (my greenhorn days) I was using 3 brokers. One was for warrants.
A spruiker from the warrants shop called me one day to say that XYZ was a 'long'. Buy now. The appropriate warrant was selected and IN I went.
Overnight, the warrants desk reduced the Implied Volatility factor. Less IV means a lower warrant 'value'. It's one of the 4 components in the formula.
The next morning, before open, my warrant's price dropped from 13 cents to 10.5 cents.
Having no recourse I closed the position and let the spruiker know what I thought of his house.