They are private equity investments and not investments in companies on the public markets so are dissociated from the vagaries those markets have. They are relatively illiquid though with investment horizons in the 5 - 7 year range typically. Recent example of a WCAS company that sold is
Kindred and some recent purchases are
here and
here. Probably was posted elsewhere but US Acute Care (the EM equivalent of USAP) bought their way out of WCAS recently.
I have friends in USAP (and know many who have left too). Their experience with USAP stock appears to be a mixed bag with the earlier guys doing well and the later guys just ok (based on what they will discuss). I haven't gotten a feel for their WCAS fund investments. Could be due to where they are in the investment horizon.