On Friday four men raided the Total Produce offices in Birmingham Wholesale Market at 10.30am, threatening staff before making off with a substantial amount of cash.
Witnesses claim the men entered the market in a van, and fled in a silver Audi.
Manager Chris Sydenham said two members of staff were thrown onto the floor during the attack on the business, but no weapons were used.
“It has been very upsetting for the staff,” he added. “It’s not something we ever expected.”
The incident did not disrupt orders, and the business has been open and operating since the raid. West Midlands Police said to date no one has been arrested.
Detective sergeant Jamie Mason, from Force CID, said: “This was a very serious crime, which has left a trader badly shaken and out of pocket.
“We’re doing everything we can to find those responsible, and I would urge anyone with information that may help to get in touch."
Anyone who has not yet spoken to police but who believes they can help should call Det Sgt Mason on 101. People who don’t want to speak with police officers directly can contact the independent charity Crimestoppers anonymously on 0800 555 111.