- A.H. Andrews & Co.1
- A.H. Montague & Son2
- A.H. and L. Building Corp.2
- A.L. Lyon Co.1
- A.M. Bing and Son Realty Corp.4
- A.P.S. Realty Corp.1
- A.S. Barnes & Co.3
- A.T. Demarest & Co.1
- A.Y. McDonald & Morrison Mfg. Co.1
- ABC Video Enterprises3
- AMIH Housing Services, Inc.1
- Aaron A. Colter & Co.1
- Aaron Green Co.13
- Aaronson and Heidrich3
- Abbott Hotels1
- Abbott and Adams, Inc.3
- Abbott and Costello (Comedy team)1
- Abbott, Karl P.2
- Abe Saul Construction Corp.1
- Abel Bros. & Co.2
- Abel, Smith & Co.1
- Abingdon Court, Inc.1
- Abraham, F. Murray1
- Abram French Company2
- Abramovitz, Max, 1908-20043
- Abramowitz, M.L.1
- Abramowitz, Samuel1
- Abrams, Philip, 1939-2
- Abrams, Ruth, 1912-19862
- Academy Developers, Inc.1
- Ackerman, Frederick L.8
- Ackerman, James S.1
- Ackman Brothers1
- Acme Copying Company1
- Acme Rubber Manufacturing Co.1
- Adams and Co. Real Estate2
- Adams, Harry S., Mrs., active 191252
- Adams, Harry S., active 191252
- Adams, Herbert, 1858-19458
- Adams, Jessie, ca. 1871-19414
- Adams, M. H., active 19051
- Adams, Mary, 1835-190812
- Adams, Nicholas, 1947-1
- Adams, William, 1861-19394
- Addison Hall Inc.2
- Adelsohn, Edward M.1
- Adephi Homes, Inc.1
- Adjmi, Morris, 1959-1
- Adler and Sullivan6
- Adler, Morris Bernard12
- Adrian Builders, Inc.1
- Advice Realty1
- Aetna National Bank1
- Aetna Rubber Co.1
- Affiliated Developers, Inc.2
- Ageloff, Samuel1
- Agol Realty Corp.1
- Agrest, Diana1
- Aikin, Lambert & Co.2
- Ailes, Roger1