Armstrong joins The Sun from The Times where she has been retail editor since 2019.
Armstrong started her financial journalism career at City AM in 2008 reporting on the financial crisis before moving to cover mergers and acquisitions for Mergermarket and then The Telegraph.
She has focused on retail for the last seven and a half years, initially at The Telegraph and as retail editor at The Times since July 2019.
Armstrong commented: “I’m really excited to be joining The Sun as business editor at such a critical time. The cost of living crisis means there is going to be huge interest in how businesses are directly impacting readers’ lives and their wallets.
“I’m looking forward to being responsible for a buzzy and feisty section and breaking big consumer news – celebrating success where it’s due and holding feet to the fire when it’s required.”
Victoria Newton, editor-in-chief of The Sun said: “I am really pleased Ashley is joining us at a time when Sun readers are turning to us to help them navigate the cost of living crisis.
“Her role is more integral than ever as we fight for hard up Brits by exposing rip-offs and holding to account government and big businesses to help save them money.”
Ashley will start her new role in the summer.