An ampersand will incorrectly be interpreted as a special HTML character and NOT be included.
I attached an example QFX file. The name of the transaction "P&C GROCERY" will be interpreted by ofxdump / GnuCash as "P GROCERY", with an error message stating: "reference to entity "C" for which no system identifier could be generated"
Changing the "&" to "&" will cause libofx to read it correctly as an ampersand, but I was surprised that libofx was reading it as if it was an HTML file. It probably has to do with the use of the OpenSP library.