API insertRecords fails when company contains an ampersand

My Zoho InsertRecords API calls are working okay, except I am unable to add a lead with a "company" that contains an ampersand (&). In this case the company is Texas A&M University. If I change "&" to "and" my code works okay.

I am using PHP, and using urlencode(), rawurlencode(), and htmlentities() on the company first had no effect. In all cases, I get no response back from Zoho (no error or anything -- the curl buffer is empty), and the record has not been added.

Is it possible to add Leads with a company whose name contains an "&"?