How does HSBC send your PDFs? If you're receiving them on an iPad or iPhone, you probably would receive them either in an email or on the web.
If they send you an email in Mail, click on the PDF in Mail and you can preview it. Then click the Share button and choose Open with, then select Adobe Reader.
If they send you a web page which you're viewing in Safari, click on the PDF to preview it. Then click the Share button and choose Open with, then select Adobe Reader.
