Stocks Market - Mansion House Street, London, UK - Blue Plaques on Waymarking.com

The blue plaque reads:

The Corporation of

Adjoining this spot
stood the
Stocks Market
1282 - 1737

the City of London

The British History website tells us about the stocks market and derivation of its name:

The present palace of the Lord Mayor stands on the site of the old Stocks' Market, built for the sale of fish and flesh by Henry Walis, mayor in the 10th year of the reign of Edward I. Before this time a pair of stocks had stood there, and they gave their name to the new market house. Walis had designed this market to help to maintain London Bridge, and the bridge keeper had for a long time power to grant leases for the market shops. In 1312–13, John de Gisors, mayor, gave a congregation of honest men of the commonalty the power of letting the Stocks' Market shops. In the reign of Edward II. the Stocks let for £46 13s. 4d. a year, and was one of the five privileged markets of London. It was rebuilt in the reign of Henry IV., and in the year 1543 there were here twenty-five fishmongers and eighteen butchers. In the reign of Henry VIII. a stone conduit was erected. The market-place was about 230 feet long and 108 feet broad, and on the east side were rows of trees "very pleasant to the inhabitants." On the north side were twenty-two covered fruit stalls, at the south-west corner butchers' stalls, and the rest of the place was taken up by gardeners who sold fruit, roots, herbs and flowers. It is said that that rich scented flower, the stock, derived its name from being sold in this market.