Hall will leave the global bank - and the PR industry - at the end of August, when she takes a new role as partner at CMi, a board-level mentoring organisation.
These are the latest changes in the bank's marcoms arrangements after it appointed a new marketing chief in April and moved its global corporate PR and public affairs account from FTI to Finsbury last year.
Hall joined HSBC as head of public affairs in November 2015, prior to which she was the deputy director-general of UK business group the CBI. Reporting directly to chair Douglas Flint and based in London, hers was a new role in which she oversaw external corporate media relations, social media and other areas, leaving head of global comms Pierre Goad to oversee internal comms.
Her external comms duties have now been passed to Goad, while public affairs are now being handled by Sir Sherard Cowper-Coles.
Formerly Britain's ambassador to Israel, Saudi Arabia and Afghanistan, Cowper-Coles was previously head of government affairs at HSBC. He initially joined the bank as an adviser and has since held other roles in its Middle Eastern operations.
Goad joined the bank from Zurich Financial Services in 2011, initially as co-head of comms alongside Charles Naylor, who now works for the CBI. Goad's full title is group head of employee insight and communications.
He told PRWeek he was "delighted to be resuming management of HSBC’s combined comms function".
Hall said: "HSBC is a fantastic company and it has been a great privilege to work here and develop a more proactive approach to communications and engagement over the past few years.
"I am very excited to be joining CMi. I am passionate about leadership development and the role of business in driving economic growth and increasing prosperity for all. This role will enable me to combine my interest in business and leadership with the opportunity to help grow a small, entrepreneurial business."
HSBC's in-house team was a double winner at last month's PRWeek Global Awards.