President Donald Trump in February ordered Treasury to halt what he called the "wasteful" minting of pennies, prompting gas stations, fast-food chains and big-box stores to adjust prices and round cash transactions.
Treasury said rising production costs and rapidly changing consumer habits and technology had made production of pennies "financially untenable" and unnecessary, noting that it costs 3.69 cents to make each penny, up from 1.42 cents a decade ago.
Production of circulating pennies was suspended months ago, Mint officials said, but an unspecified number of additional one-cent coins - marked with an Omega symbol to signify the last of their kind - were made to be auctioned off in December.
The five pennies pressed on Wednesday will be part of that batch, said Robert Kurzyna, superintendent of the Philadelphia Mint. Details of the auction will be released shortly. Those pennies could technically be used for circulation, unlike collector coins, which are shinier and made differently.
The Philadelphia Mint produced 232 of Omega-stamped coins for the auction, one for each year the penny was produced, plus three for display at Treasury and other institutions, a source familiar with the matter said. It also produced 235 gold pennies, the source said.
It was unclear whether additional pennies were pressed for the auction at the Denver Mint, where pennies were also made.
US Mint Acting Director Kristie McNally said the first and last of the coins to be auctioned could fetch around $US100,000 ($A153,000). All proceeds will be used to fund Mint operations, with any excess to be transferred to the US Treasury, she said.
Suspending production of the penny is expected to save the US Mint about $US56 million ($A86 million) a year, Treasury said. Pennies will remain legal tender, with an estimated 300 billion of them in circulation, "far exceeding the amount needed for commerce," Treasury said.
The US is joining other countries, including Canada, Australia, Ireland and New Zealand, in phasing out their lowest-value coins, rounding cash transactions up or down to the nearest five cents while keeping electronic payments exact.
The penny was first issued by the government in 1793. Since 1909, the profile of President Abraham Lincoln has adorned the obverse side of the coin made of zinc and copper.
In fiscal 2024, pennies accounted for 57 per cent - or 3.2 billion - of the Mint's total production of 5.61 billion circulating coins. The Mint will continue to produce collector versions of the penny in limited quantities, Treasury said.
A Mint official said some gold pennies were also planned.
Supporters of the penny have argued that it helps keep consumer prices lower and is a source of income to charities.
For many Americans, however, the coin has become a nuisance that ends up being discarded in drawers, jars and piggy banks.
with AP
