what insurance company specializes in catastrophic reinsurance,  has
produced an average return on equity of 15% over the past 17 years,
and has cash and investments of over a billion dollars?

Hi!
I don't think there are insurance cos which specialise in catatrophic
insurance. But there are re-insurers. When an insurance co wants to
spread the risk since it can't bear the burden alone, they seek
reinsurance.
There are any number of reinsurers world wide. Do you want me to research further?

This is an insurance company that reinsures small percentages of many
catastrophic policies - not a giant company, but know that they have
investments of over a billion $ and assets over 1 billion $ - and that
these clues might be sufficient to determine the company name.