Shares in Stanley Gibbons fell over 8% on Thursday, after the collectibles group warned that its annual results will be below market expectations.The London-listed company said it expected group sales and profitability for the year to 31 March will show a "significant" increase in growth compared to the previous 12 months, on the back of contribution from recent acquisitions.However, Stanley Gibbons said a number of anticipated high value sales in its retail business had not been completed before the end of the financial year, meaning results will be "materially below" current market expectations."Although disappointed by our failure to deliver the high value sales in 2014/15 necessary to meet market expectations, the board is satisfied with the progress which has been made in the past year," said group chairman Martin Bralsford."We are delivering on our long term strategic objectives, which have the potential to transform both the business and the collectibles market as a whole."The company said a number of technical development projects, geared towards launching a global collectibles online trading platform, have progressed in line with plans and the new website is expected to be launched in May.Stanley Gibbons shares were down 8.27% to 244.00p at 12:46 on Thursday.