Area code 312

Area code 773 serves Chicago, Illinois, outside the Loop and the innermost neighborhoods. Originally, all of Chicago and its suburbs were in area code 312. Then, in 1989, area code 708 was created for the suburbs, leaving the city itself in area code 312. By the mid-1990s, Chicago's continued growth and the proliferation of cell phones and pagers made it apparent that the city needed a new area code. It was decided to split off all of the city outside the downtown area as 773. The new area code went into effect on October 12, 1996. Permissive dialing of 312 continued across Chicago until January 11, 1997. On August 10, 2007, the Illinois Commerce Commission announced that area code 872 would overlay area codes 312 and 773; it went into service on November 7, 2009. The Illinois side of the Chicago area–312/773/872, 708, 847/224, 630/331 and portions of 815/779–is one of the largest local calling areas in the United States; with few exceptions, no long-distance charges are applied from one portion of the metro area to another.

Area code 872 is a North American Numbering Plan overlay of telephone area codes 312 and 773 in Chicago, Illinois, and entered service on November 7, 2009. Its overlay status means it is assigned only to new numbers in the area and not to existing numbers using the 312 and 773 area codes. It is the third overlay area code in the region and the tenth area code to serve northeast Illinois.As early as 1998, Neustar, which administers the North American Numbering Plan, had recommended a third area code for Chicago, estimating that 312 and 773 would both exhaust by 2001. However, the Illinois Commerce Commission implemented a series of conservation measures that staved off the need for a new area code. By 2008, a combination of population growth and a large growth in cell phone usage forced the implementation of 872.With the implementation of 872, all local calls in Chicago must be dialed with the full 11-digit phone number (10 digits from cell phones).The Illinois side of the Chicago area–312/773/872, 708/464, 847/224, 630/331 and portions of 815/779–is one of the largest local calling areas in the United States; with few exceptions, no long-distance charges are applied from one portion of the metro area to another.

The Field Building, also known as the LaSalle National Bank Building and Bank of America Building is an art deco office building at 135 South LaSalle Street in the Loop community area of Chicago, Illinois in the United States. The building was designated a Chicago Landmark February 9, 1994.

Harris Bank Addition II is a 510 ft (160 m) tall skyscraper in Chicago, Illinois. It was completed in 1974 and has 38 floors. Skidmore, Owings and Merrill designed the building in the International style which is the 83rd tallest in Chicago and has 592,000 sq ft (55,000 m2) of floor space. It houses offices and a branch for BMO Harris Bank. The building is located at the southeast corner of Monroe and LaSalle Streets and is set back from the property line of Monroe Street to allow a small plaza and fountain. The addition is part of the Harris Bank complex which consists of the original 20-story building constructed in 1911, a 23-story structure to the east constructed in 1958 and the 38-story tower to the west. The 1958 building was also designed by Skidmore, Owings and Merrill and both additions are faced with glass and stainless steel. The 1958 structure bears the address of 111 West Monroe Street and the 1910 building is at 119 West Monroe Street. Together, these two buildings contain 611,000 sq ft (56,800 m2). All three buildings are connected on 15 floors allowing occupants to cross through the entire complex. The street levels of both additions is recessed to allow for a narrow pedestrian arcade. The second addition houses a Harris Bank branch on the street level while the first addition houses retail stores. The 1910 building was designed by Shepley, Ruttan and Coolidge in the neoclassical style and is 285 ft (87 m) tall. The lower five floors are faced with pink granite while the upper floors are red brick. Two bas-relief sculptures of lions which were used in the bank's logo until a name change in 2011. Above the entrance are four granite columns which extend from the second to fifth floors. The original cornice was removed at an unknown date. The entire complex is managed by CommonWealth Partners, Management Services.

The Home Insurance Building was a skyscraper that stood in Chicago from 1885 to 1931. Originally ten stories and 138 ft (42.1 m) tall, it was designed by William Le Baron Jenney in 1884 and completed the next year. Two floors were added in 1891, bringing its now finished height to 180 feet (54.9 meters). It was the first tall building to be supported both inside and outside by a fireproof structural steel frame, though it also included reinforced concrete. It is considered the world's first skyscraper. The building opened in 1885 and was demolished 46 years later in 1931.

The Montauk Building – also referred to as Montauk Block – was a high-rise building in Chicago, Illinois.

The West Loop–LaSalle Street Historic District is a historic district centered on LaSalle Street in the western Chicago Loop. The district was added to the National Register of Historic Places on June 1, 2013. A boundary increase on July 24, 2017, added two buildings at 330 S. Wells Street and 212 W. Van Buren Street to the district.The district encompasses Chicago's financial center, which is anchored by the Chicago Board of Trade Building, and also includes several of its major banking institutions including the Federal Reserve bank and several government buildings. Development in the district began in 1873 and, with the exception of a lull during the Great Depression and World War II, has continued through the present day. Most of the district's buildings are high-rises with at least ten stories, with the tallest being the 49-story One North LaSalle Building. Many of Chicago's prominent architectural firms designed buildings within the district, and the buildings feature styles such as Classical Revival, Chicago School, Art Deco, Romanesque Revival, and International. Significant buildings within the district include the Federal Reserve Bank of Chicago, Chicago City Hall, and several office buildings for large banks and insurance companies.

The Center for Research in Security Prices (CRSP) is a provider of historical stock market data. The Center is a part of the Booth School of Business at the University of Chicago. CRSP maintains some of the largest and most comprehensive proprietary historical databases in stock market research. Academic researchers and investment professionals rely on CRSP for accurate, survivor bias-free information which provides a foundation for their research and analyses. As of 2020, CRSP claims over 500 clients. The name is usually pronounced "crisp". CRSP was founded in 1960 by James H. Lorie (professor of finance and director of research) and Lawrence Fisher (assistant professor of finance) of the University of Chicago, with a grant from Merrill Lynch, Pierce, Fenner & Smith. Its goal was to provide a source of accurate and comprehensive data that could be used to answer basic questions about the behavior of stock markets. The first effort of the Center was the production of a database consisting of monthly stock prices on the New York Stock Exchange for all common stocks from 1926 to 1962. Dividends, shares outstanding, capital changes, and delisting information was also included. Taken together, this data made possible the first comprehensive study of the rates of return on common stocks. Since then the database has been kept up to date to the present day, daily data has been expanded back to 1926, and other exchanges and financial instruments have been added. On January 1, 2020, CRSP spun off from Chicago Booth and became CRSP, LLC. CRSP, LLC is an affiliate of the University of Chicago Booth School of Business. CRSP's flagship databases include: Common stocks on the NYSE from 1926, AMEX from 1962, and NASDAQ from 1972 CRSP Indexes NASDAQ and S&P 500 Composite Indices NASDAQ and AMEX Industry Indices US Treasury bonds Survivor bias-free mutual funds Market capitalization reports; Proxy graphs for 10-K SEC filings Other custom datasetsIn partnership with Compustat, CRSP provides the CRSP/Compustat Merged Database, and in partnership with the Ziman School of Real Estate at UCLA's Anderson School of Business, the CRSP/Ziman REIT Data Series.

The Continental and Commercial National Bank is a historic office building located at 208 S. LaSalle Street in Chicago's Loop. The 21-story building was built in 1911-14 for the Continental and Commercial National Bank, at the time one of the largest banks in the nation. Architect Daniel Burnham designed the building in the Classical Revival style; Burnham, who was perhaps best known for his 1909 plan of Chicago, was a proponent of the style and used it in office buildings in multiple cities. The building's main entrance features a three-story colonnade with eight Doric columns; the eighteenth through the twentieth floors feature a matching colonnade, which forms the building's capital. A frieze and belt course separate the fourth and seventeenth floors from the shaft of the building, giving the building a small amount of horizontal emphasis. An open court occupies the center of the building, allowing natural light to reach its interior offices.The building was added to the National Register of Historic Places on February 14, 2007.Prior to merging with the Continental National Bank to form the Continental and Commercial Nation Bank, the Commercial National Bank was previously located in the now landmark Commercial National Bank Building.

The Rookery Building is a historic office building located at 209 South LaSalle Street in the Chicago Loop. Completed by architects Daniel Burnham and John Wellborn Root of Burnham and Root in 1888, it is considered one of their masterpiece buildings, and was once the location of their offices. The building is 181 feet (55 m) in height, twelve stories tall, and is considered the oldest standing high-rise in Chicago. It has a unique construction style featuring exterior load-bearing walls and an interior steel frame, providing a transition between accepted and new building techniques. The lobby was remodeled in 1905 by Frank Lloyd Wright. From 1989 to 1992, the lobby was restored to Wright's design. The building was designated a Chicago Landmark on July 5, 1972, and was added to the National Register of Historic Places on April 17, 1970 and listed as a National Historic Landmark on May 15, 1975.

U.S. Bank Building, formerly 190 South LaSalle Street, is a 573 feet (175 m) tall skyscraper in Chicago, Illinois. It was completed in 1987 and has 40 floors. Johnson/Burgee Architects designed the building, which is the 57th tallest building in Chicago. From 1988-2016 the lobby of the building featured a tapestry by Helena Hernmarck titled "The 1909 Plan of Chicago" depicting the Civic Center Plaza proposed in the Burnham Plan of Chicago.In May 2013, U.S. Bank announced it agreed to increase its leased space in the structure from 66,000 square feet (6,100 m2) to 110,000 square feet (10,000 m2). The terms of the lease also gave the bank naming rights for the building through 2026.

The Clark Adams Building, also known as the Bankers Building, is a skyscraper located at 105 West Adams Street in Chicago, Illinois. The building was designed by the Burnham Brothers who designed other buildings in Chicago such as the Carbide and Carbon Building. The building stands at 476 feet tall and has 41 floors. Construction of the Clark Adams Building began in 1926 and was completed in 1927.