's Earl A. Thompson and Jonathan Treussard, "The Tulipmania: Fact or Artifact?", provides an alternate explanation for Dutch tulip mania: that it was not caused by irrational speculation, but rather by a Dutch parliamentary decree (originally sponsored by Dutch investors made skittish by the Thirty Years' War then in progress) that made the purchase of tulip-bulb "futures contracts" a nearly risk-free proposition:
...both the famous popular discussion of Mackay and the famous academic discussion of Posthumus, 1929, point out a highly peculiar part of this episode. In particular, they tell us that, on February 24, 1637, the self-regulating guild of Dutch florists, in a decision that was later ratified by the Dutch Parliament, announced that all futures contracts written after November 30, 1636 and before the re-opening of the cash market in the early Spring, were to be to [sic] interpreted as option contracts. They did this by simply relieving the futures buyers of the obligation to buy the future tulips, forcing them merely to compensate the sellers with a small fixed percentage of the contract price.
Given data about the specific payoffs present in the futures and option contracts, the authors determine that tulip bulb prices in fact hewed closely to what a rational economic model would dictate: "tulip contract prices before, during, and after the 'tulipmania' appear to provide a remarkable illustration of market efficiency."