A reward of £5,000 has been offered for information leading to the safe return of a missing student who has not been seen since 26 December.
Sophie Smith, 21, left her home in Gorleston, Norfolk, dressed in shorts and a vest top at 03:00 GMT.
Jason Smith, from RJS Builders, based in the town, has put up the reward.
On Friday, police said it was likely the 21-year-old had gone into the sea. The coastguard and police helicopter has searched the shoreline.
In a separate gesture, Norfolk artist Ruddy Muddy, who creates pictures of celebrities and personalities in mud on vehicles, has designed an appeal on a van to draw attention to the search for the University of East Anglia student.
Ms Smith, who had been receiving treatment for depression and anxiety, is described as white, about 5ft 8in (1.73m), of slim build with shoulder-length blonde hair.
It is believed she was wearing a dark-coloured vest top and light-coloured shorts.