The event, which was due to take place in Singapore this week, was cancelled at the eleventh hour in response to the US air strikes on Afghanistan. In the letter, Patrick Neutjens, director of Sibos, says Swift had "no choice" but to cancel the show.

"The risk was that something could happen, anywhere anytime and our community would all be in the wrong place, far from where they needed to be," he says. "Moreover, many of our delegates were in the process of imposing travel restrictions. The global security situation was obviously very uncertain. Poor attendance would have affected the very essence of this event."

His words are likely to fuel resentment among exhibitors, many of whom believe that Swift should have cancelled the event much earlier. Swift continued to reassure exhibitors that Sibos would go ahead as planned, despite evidence that senior European and US delegates were pulling out and sending junior and local staff as their proxies. By the time Swift pulled the plug, many vendors had already committed to heavy spending on stand construction, marketing collateral, and travel costs.

Swift has said that it will refund the charges for stand space rental for exhibitors. "Unfortunately we cannot go further," says Neutjens. "Swift cannot give you compensation for other costs you incurred such as travel, stand building and social events."

The limited refund policy is unlikely to appease vendors, who point out that floor space rental is a relatively minor portion of the total Sibos spend.

Neutjens says Swift is open to further suggestions from exhibitors on how it can help the vendor community make up for lost opportunities and deliver a return on investments.