The open-outcry trading floor of the New York Mercantile Exchange in lower Manhattan will shut down after markets close Friday, the latest step in the inexorable shift toward electronic trading.

CME Group Inc., which owns the Nymex, said in April that the New York trading floor would close at the end of the year after the share of options volume executed there had dwindled to just 0.3% of the company’s overall energy and metals volumes. Chicago-based CME had already stopped futures trading on the Nymex floor last year.

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