The central section of the block contains the original structure at 18 Broad Street, designed in the Classical Revival style by George B.

The Broad Street colonnade, an icon of the NYSE, contains a pediment designed by John Quincy Adams Ward and Paul Wayland Bartlett, depicting commerce and industry.

Three additional trading floors were added in the late 20th century to accommodate increasing demand, and there were several proposals to move the NYSE elsewhere during that time.

[26][27][28] Unlike the Roman sources from which the design of 18 Broad Street's facade is derived, the building has entrances at basement level on both sides, rather than grand staircases leading to the colonnades.

[30] Above the colonnade on Broad Street is a triangular pediment, originally carved by the Piccirilli Brothers[38] and designed by John Quincy Adams Ward and Paul Wayland Bartlett.

[55] The machinery, electric and steam plants, maintenance workers' rooms, and vaults are in the basement and subbasement underneath the first-story trading floor.

[53][56][58] The surrounding area had an atypically high water table, with groundwater being present a few feet below ground, partially because Broad Street was the former site of a drainage ditch.

[35][65] The northern and southern walls originally had colored "checkerboards" with over 1,200 panels, which could be lit in a variety of patterns to flash messages to members on the floor.

[71][72] Abutting the trading floor on higher levels were doctors' rooms, baths, and barbershops for NYSE members,[43][56][57] in addition to call bells that could be rung whenever someone needed a broker to come down.

[73] Post included a large interior light shaft on 18 Broad Street's upper stories as part of the building's design.

The broker organization began renting out space exclusively for securities trading, using several locations for the next half-century, including the Tontine Coffee House.

[86] The plans had to consider the lot's complex topography, unusual shape, underlying ground, and the removal of the large deposit vault.

[106] The publicist Ivy Lee wrote that the structure was to "be both monumental architecturally and equipped with every device that mechanics, electricity or ingenuity could supply with every resource needed to transact the security trading for the commercial center of the world".

[104][107] The exchange briefly contemplated an eight-to-nine-story structure with offices above its trading floor, but the NYSE ultimately discarded this proposal as unwieldy.

Various issues delayed the opening by one year, including difficulty in demolishing the old building, as well as alterations made to the original plan during construction.

[53] R. H. Thomas, a chairman of the committee that oversaw construction, justified the delay by saying, "Where so many of our members spend the active years of their lives, they are entitled to the best that architectural ingenuity and engineering skill can produce.

[133][134] The NYSE's growth stopped suddenly with the Wall Street Crash of 1929, when share prices on the exchange dropped 23 percent in two days,[135] in what was cited as one cause of the Great Depression.

[136] The NYSE trading floor was closed for over a week during the Depression, in March 1933, after President Franklin D. Roosevelt signed the Emergency Banking Act.

[153] In 1977, the media published rumors that the NYSE and the American Stock Exchange (AMEX) would merge and construct a new combined facility;[154][155] however, the merger did not occur at that time.

[154][156] As a temporary measure, the NYSE renovated its visitors' center in 1979, adding a multi-story gallery with various displays adjacent to the main trading floor.

After Olympia and York severed their involvement because of financial difficulties, a team composed of J.P. Morgan & Co., Lewis Rudin, Gerald D. Hines, and Fred Wilpon took over the project.

[163][164] Other sites under consideration included the Broad Exchange Building immediately to the southeast,[165] as well as Bowling Green at the southern end of Manhattan.

[194] When the 18 Broad Street building was completed, publicist Ivy Lee wrote: "In outer contour it suggests the columnar, monumental architecture of the ancient Greeks.

[197] Schuyler especially appreciated that the colonnades' columns visually divided the large windows behind them;[32][40] his only negative criticism was that the carving of the basement was incongruous with the rest of the design.

[199] Elizabeth Macaulay-Lewis said in 2021: "The massive building imbued the NYSE with authority, reflecting its view of itself and its role in the economy" while also providing space for a trading floor.

Stuart of Architectural Record wrote that, with the colonnades and large trading-floor windows, "the new Exchange will have a scale of its own, at once so simple and impressive as to readily signalize it among its surroundings".

[200] Conversely, Scribner's Magazine wrote in 1903 that the pediment on Broad Street was disadvantaged by its location opposite several tall buildings, "which has caused Ward to give to his figures very great scale and to diminish their number".

[201] Architectural writer Robert A. M. Stern said that the pediment's sculptures gave the building "an air of magisterial calm as it presided over the financial world's most important intersection".

In 1989, artist Arturo Di Modica installed his sculpture Charging Bull in front of the building, in an act of guerrilla art.

[207] The Fearless Girl sculpture was originally installed in 2017 facing Charging Bull at Bowling Green, but it was moved to the NYSE because of complaints from Di Modica.