Clinton will acquire all of Hallmark's shops in England and Wales. The company said these complemented its existing portfolio of retail sites.
Philip Haggard, an analyst at Nikko Europe, said: 'They appear to have got the retail sites at a discount, and paid nothing at all for goodwill.'
Hallmark, a private US company, already supplies 40 per cent of Clinton's stock. It is selling its retail arm to concentrate on card publishing.
Clinton announced increased losses of pounds 2.2m for the six months to the end of July, compared to a first-half loss of pounds 956,000 last year. A 2 per cent increase in turnover was not enough to compensate for the higher costs of operating 14 more shops during the first six months. The interim dividend remains unchanged at 1.6p.
Mr Haggard said: 'Clinton still looks quite cheap for a retail stock.' He forecast profits of pounds 2.4m for the full year, implying earnings per share of 9.4p and a prospective price-earnings ratio of 11.Reuse content