Incident: Two pricing bots priced a book at $23.7 million

Module 11 · Incident file · About 30 minutes

What happened

On 22 April 2011 Michael Eisen, a biologist whose lab studies the fruit fly Drosophila, published "Amazon's $23,698,655.93 book about flies" on his blog (michaeleisen.org, read here from the Internet Archive's copy). A few weeks earlier a postdoc in his lab had gone to buy Peter Lawrence's The Making of a Fly, an out-of-print 1992 textbook. Amazon listed 15 used copies from $35.54 and "2 new from $1,730,045.91 (+$3.99 shipping)".

The two sellers, profnath and bordeebook, looked legitimate, with over 8,000 and 125,000 ratings in the past year. The next day both prices had gone up, to nearly $2.8 million each. By the end of that day the higher one was $3,536,675.57. Eisen kept watching. "The pattern continued perfectly for the next week."

The price peaked on 18 April. On 19 April profnath's price fell to $106.23, and bordeebook followed to $134.97. "Somebody ultimately noticed," Eisen wrote. He does not say who, or whether anyone tried to buy the book. Until then, for at least a week, the listing showed shoppers a price no person had chosen.