With hours to go before the winner of this year’s Man Booker prize is announced, former Waterstones bookseller Graeme Macrae Burnet’s tale of murder in a Scottish crofting community, His Bloody Project, is comfortably outselling the rest of the shortlist. But Madeleine Thien’s Do Not Say We Have Nothing has emerged as the frontrunner at the bookies.

Best sales … Graeme Macrae Burnet. Photograph: Alastair Grant/AP

Published by tiny Scottish independent publisher Saraband, His Bloody Project – described as “a fiendishly readable tale that richly deserves the wider attention the Booker has brought it” in the Guardian’s review – had sold just one copy in the week before it was longlisted for the £50,000 prize in July. According to statistics from Nielsen BookScan, its life sales at that point were just 561 copies. Following the longlist announcement, it sold 5,622 copies, and in the weeks since the six-strong shortlist was unveiled on 13 September, it has sold an additional 24,079 copies – well ahead of the second bestselling title, Ottessa Moshfegh’s thriller Eileen, which has sold just over 11,000 copies since the shortlist was announced.

“Our bestselling title by some distance is His Bloody Project. A cracking plot combined with the literary kudos bestowed upon it by the Booker judges seems to have created a kind of commercial alchemy – which has made it not only our bestselling Booker title but one of our bestselling titles full stop,” said Waterstones fiction buyer Chris White. “Also, from a personal perspective, it’s wonderful to see a former Waterstones bookseller having such success.”

Shortened odds … Madeleine Thien. Photograph: Daniel Leal-Olivas/AFP/Getty Images

At the bookies, however, Thien’s story of a young woman who has fled the Tiananmen Square protests in China, and who is invited into the home of 10-year-old Marie and her mother, is out in front. Do Not Say We Have Nothing was backed from 12/1 to 7/4 favourite at William Hill, and is also 2/1 favourite at Ladbrokes. William Hill has Deborah Levy’s Hot Milk at 11/4, His Bloody Project at 4/1, Paul Beatty’s The Sellout at 5/1, David Szalay’s All That Man Is at 7/1 and Eileen at 8/1 to win the prize.

“Thirty-four per cent of all the stakes on the outcome of the Booker have been for Madeleine Thien, with 26% of all bets placed on her,” said William Hill spokesman Graham Sharpe, “The Canadian author tops each of these categories and has been backed down from 12/1 when the longlist was issued, to 5/1 when the shortlist was announced, then to 3/1 and now to 7/4 clear favourite, relegating Deborah Levy to second favourite.”

At Ladbrokes, Alex Donohue said: “The literary runners and riders are still tightly bunched entering the final straight. The trends favour a win for either Thien or Levy, but in a year of shocks and surprises it wouldn’t be that much of an upset at all for anyone to take the prize.”