There is no record of Thayer's early activities. It is possible he may have been associated with relatives, for at the time there were Thayers in Lancaster who were engaged in trade with China. The fact that he established his own business on Boston's Central Wharf, where many of the city's merchants maintained counting-houses, also suggests that his experience may have been in foreign commerce. Thayer kept his wharf location only two years. In 1826 he moved to 47 State Street, the center of Boston's financial district, where most other stock and exchange brokers and all but one of the city's fifteen chartered commercial banks had offices. He continued in business on State Street until his death in 1857.
Like many other private banking and brokerage houses at the time, Thayer's appears to have been a one-person organization. The firm's initial capital is unknown, but it was believed to have been small. At the time of his death, the Boston Evening Transcript noted that Thayer had started in business "with no inheritance except a good name".
Other aspects of the firm's early years are equally obscure. Staff size is unknown as is its composition and turnover. The business probably was conducted with no more than one or two clerks, almost certainly with no more than six, the number employed at the time the firm was dissolved in 1865.
Contemporary business directories classified the firm as a brokerage house, usually listing it with "stock and exchange" brokers. Its functions, however, included many other activities beyond those commonly associated with present-day brokerage firms. Some of Thayer's services, such as raising new capital for business and governments, buying and selling securities for clients, and providing financial advice to corporations and counseling wealthy individuals on their investments, foreshadowed on a small scale some of the functions of present-day investment bankers. Others were typically those of pre-Civil War and later nineteenth-century private bankers. Thayer dealt in foreign exchange, but did not participate actively in foreign trade. He accepted some deposits, chiefly from clients seeking investments. These funds, together with some of his own, he invested in a variety of enterprises, mostly New England banks, insurance companies, cotton manufacturing firms, real estate, as well as railroads.
Massachusetts law prohibited private bankers from issuing their own notes for circulation as money, and Thayer, unlike some of his contemporaries in other states, appears to have adhered strictly both to the intent and letter of the law. His apparent refusal to engage in any money-creating activities probably was the only significant difference in functions between his banking house and Boston's chartered commercial banks.
But it was Thayer's services to a relatively small group of elite Boston business managers and investors that augmented his reputation and fortune and, according to the Boston Evening Transcript, made him "the head of a banking house second to none in the country." Thayer shared many of his clients' values and outlook; his family background was similar to theirs, and so was that of his wife, Anna Francis, the daughter of Ebenezar Francis, one of Boston's richest men, a ship-owner, merchant, and financier.
Thayer was a conservative banker and cautious investor. His involvement with railroad enterprises illustrates these qualities. At a time when railroads were widely hailed as the solution to the country's pressing need for cheap and improved land transportation, Thayer, like many other Boston bankers and capitalists, was neither an active supporter of nor a heavy investor in these projects. His railroad interests in the 1830s included three Massachusetts carriers. In two of them, the Boston and Worcester (incorporated in 1831) and the Western (chartered in 1833), Thayer was a small initial investor, subscribing to five shares of the former and twenty of the latter. For the third road, the Eastern (incorporated in 1836), he was a late investor. His first purchase of this road's stock occurred in 1839, after its viability had been proved and further state aid was forthcoming. Thayer's involvement in early railroad finance was modest and largely passive.
The same cannot be said of Thayer's other activities. These were growing rapidly and were widespread. During the later 1830s, he had accounts with some eighteen brokerage firms in nine different cities, from Amherst, New Hampshire, to New Orleans, Louisiana. Six of his correspondents were in New York City, one of the more important of whom was Cammann & Whitehouse, a highly respected and energetic firm. In Washington, D.C., Thayer's correspondent was William Wilson Corcoran, who was then operating his own brokerage house.
There is no evidence to indicate the nature of Thayer's transactions with his correspondents, but his ledger shows that several of his accounts were active and involved sizable sums. Such was the one with Cammann & Whitehouse. A sample month in 1839 recorded thirteen entries with total debits of nearly $125,000. Another of Thayer's active accounts was with A. H. Dorr & Co., a New York City brokerage firm. For January 1839, Thayer's total debits with this house amounted to nearly $370,000, with some twenty-eight transactions involved. These and other ledger entries substantiate contemporary opinion that Thayer's business was relatively large, widespread, and profitable. Earlier in the decade his wealth had been estimated at $200,000; a few years before his death a contemporary chronicler claimed Thayer was worth about $1.5 million. Bostonians considered him an influential capitalist, "the possessor of a most ample fortune," in the words of the Boston Evening Transcript.
State Street bankers and brokers regarded Thayer as a leading figure in the financial district. He was one of thirteen brokers who helped establish the Boston Stock Exchange in 1834, then called the Boston Broker's Board. Its original quarters, on the upper story of the Washington Bank Building at 47 State Street, were at the same address Thayer occupied at the time. In 1854 he also took an active part in organizing the Boston Board of Trade.
Thayer continued in business for himself until 1839. In that year he admitted to the firm his younger brother, Nathaniel, who was then a few months shy of his thirty-first birthday. Educated at the Lancaster Academy, Nathaniel, like his brother, also violated family tradition by opting for a business career instead of attending Harvard. Nathaniel Thayer was sixteen years old when he moved to Boston to accept a clerkship with a Long Wharf merchant trading with the West Indies. He stayed with this firm six years, long enough to learn the business and accumulate some capital. In 1830, at age twenty-two, he became a partner of Elisha Preston, another prominent Long Wharf trader dealing in West Indian goods. During his years with Preston, young Thayer also engaged in other profitable activities. In 1832, together with his partner and three other Boston merchants, he joined a syndicate organized to hunt whale in the Pacific, Indian, and Atlantic oceans. The group purchased four ships and operated them profitably until 1840; a year after young Thayer had left Long Wharf to join his brother on State Street.
