I found the following on roaring-twenties.com.
The Reo was made in the U.S. from 1904 - 1936. In 1904 the Lansing, Michigan company, known as R.E. Olds Co., was renamed to Reo Car Co. and then Reo Motor Car Co.
The Reo name derives from the initials of Ransom E. Olds who left Oldsmobile to form a new company. The first Reos were single-cylinder 8 hp runabouts with under-floor engines, dummy bonnets, planetary transmissions, and chain drive. They sold
for $685, reduced to $500 by 1909. A companion 16hp twin at $1,250 had a capacity of 3.4 litres and a carburetor for each cylinder. These represented the company's main effort up to 1909, though a short-lived four had been marketed in 1906. 1911/12 brought the Reo The Fifth, another 4-cylinder car with 3.7 litre ioe engine, which offered central change and left-hand drive for $1,065.
Reo cars were steady cars right up to the Depression of 1929 - 1931, and the company did very well with their subsequent ioe fours and sixes, which were made with V-radiators during the World War I period. In 1918, 4-cylinder cars sold
for $1,225. By 1927 there was a switch to side valves and hydraulic 4-wheel brakes
, and in 1928 the company offered the Wolverine, a cheaper car with a Continental engine which sold
for $1,195. This was the company's best year with 29,000 sold.
The Wolverine was dropped in 1929, and production centered on two versions of the Flying Cloud
. In 1936, the Reo dropped production of private cars. Trucks and buses continued to be made from 1957, as a division of White. A 1967 amalgamation with Diamond T led to a new brand name, Diamond-Reo, and in 1971 this was sold by White to become an independent make.
Source: The New Encyclopedia of Automobiles, 1885 To The Present