It comes after the group posted a £564,275 loss from £29.7 million sales in its most recent accounts filed with Companies House.
The accounts also show had debts of around £9 million.
AM has tried to contact managing director Richard Haytack but was told he was unavailable until tomorrow.
Horners has downsized considerably in recent years, after being badly hit by the collapse of main manufacturer partner MG Rover.
It currently has just two sites - Manchester (Mitsubishi, Mitsubishi LCV and Skoda) and Rochdale (Mitsubishi).
Four years ago the group also had sites in Blackburn (MG Rover), Burnley (MG Rover, Fiat, Fiat LCV), Bury (Skoda) and Eccles (Mitsubishi and MG Rover).
An industry source told AM: "The problem is that its remaining sites were built for a franchise with a 10-12% market share, but it's left with franchises which combined have at most a 2.5% share.
"The business is arguably five-times over-facilitised, but it will be very sad if it goes into administration."