on spec

Idioms  

1. Done on a speculative basis; with no assurance of profit. For example, We didn't design our house; the builder built it on spec. The use of spec as an abbreviation for speculation dates from the late 1700s.

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Example Sentences

The military still lacks the multiyear funding to fully meet its production targets, prompting some officials to ask defense contractors to add more capacity on spec ahead of actual orders.

From The Wall Street Journal • Dec. 23, 2025

Some new companies, such as Texas-based Fermi, are essentially building power plants on spec, betting that tech companies will eventually pay up for their electricity.

From Barron's • Oct. 17, 2025

Given that the vast majority of houses in America are built on spec by developers, Kate Wagner told me, home design naturally trends toward “a commonly agreed-upon design ideology that is the least offensive possible.”

From Slate • Mar. 6, 2025

So he infiltrated the militia movement on spec, as a freelance vigilante.

From Salon • Jan. 7, 2025

And as he smoked his cigarette, in laconic phrases he explained how a huge steel construction concern had gone to the wall, through building skyscrapers "on spec" and outstripping even the growth of New York.

From His Family by Poole, Ernest