The international trading group has an option to lift its 15 per cent stake to 24.6 per cent at a price of 172p a share. But that option expires on 1 July.
The two companies have been moving closer together over the past year. Stephen King, a former director of financial control at Inchcape, became finance director at Gestetner in September.
Speculation that Inchcape would mount a bid drove its share price down 8.5p to 466.5p last week, while Gestetner's price rose from 163p to 175p.
Inchcape's shares have also been under pressure recently following a profit warning in late May.
Sir David Plastow, the company's chairman, blamed disappointing trading on the strength of the yen and the Japanese recession, the downturn in continental motor markets and austerity measures in China.Reuse content