In a statement it described the discussions of a possible offer as an “unsolicited approach” and said “there can be no certainty that any offer will be made nor as to the terms on which any such offer might be made”.
It made the statement following a rise in its share price this morning.
The announcement follows a series of disposals by the stamps group in recent weeks. Last month it announced it had agreed a deal with former auctioneer and ceramics specialist Mark Law and investor Gavin Alexander to sell auctioneer Dreweatts and dealer Mallett for £2.4m.
It also agreed to sell its 25% stake in Masterpiece London for £1.4m to the majority owner of the art and antiques fair.
Stanley Gibbons' chairman Harry Wilson, who joined in May 2016, is selling off businesses to pay down debt to allow it to focus on its core stamps and coins specialism.
The share price of the Stanley Gibbons Group is up 19% to 13.3p at 11am today but it is still down by around 96% from its 2014 peak.