An industrial tribunal at Stratford, east London, ruled yesterday that Ms Walz had no contractual or non-contractual rights to the money.
Ms Walz, 36, an American living in London, claimed she was praised as "a star" by Andrew Tuckey, the former deputy chairman of Barings, when he handed her a slip of paper confirming the bonus in February 1995. Just 13 hours later, the dealings of Nick Leeson, the rogue trader, brought down the bank with losses of pounds 860m.
Ms Walz said previous bonuses had never been linked to the bank's profits. But ING, the Dutch financial services giant which rescued Barings in March 1995, argued she was one of the senior managers responsible for Leeson, who is serving six- and-a-half years in a Singapore jail for his illegal trading.
It said the agreement was informal and since the bank collapsed the next day, there was no profit-sharing pool from which she could be paid.
Ms Walz said yesterday she and her lawyers had believed her meeting with Mr Tuckey in February 1995 had "amounted to more than just a casual indication of my compensation".
But she said: "I put the question before the tribunal for the obvious purpose of seeking its independent review and to attempt to isolate what was strictly an employment issue from the complexities of the tragedy of the collapse of Barings."
"Having put the question to the tribunal, I now accept and respect its decision," she said.
ING Barings declined to comment yesterday. However, one banking source expressed relief at the decision. "It says encouraging things about accountability. There are those of us who thought it was a cheeky thing to do," one banker said.
Ms Walz is also battling to clear her name with the Securities and Futures Authority, the City regulator, which has brought charges against her in connection with the collapse of the bank. In addition, many former Barings executives, including Ms Walz, are being sued by Coopers & Lybrand, the auditors of Barings.