One-to-many is a type of trading platform where all buyers and sellers transact with a sole market operator. Whereas a normal exchange involves the operator matching buyers with sellers, a one-to-many platform operator will purchase assets from sellers and resell to buyers. All bids and offers are posted by the platform operator.


A one-to-many market involves one group or organization transacting with multiple buyers and sellers. However, in contrast to the standard "many-to-many" platform, one-to-many is rarely used in capital markets. The Commodity Exchange Act, for instance, does not recognize one-to-many markets as official trading facilities. The most infamous example of a one-to-many trading platform was Enron's EOL, an unregulated online trading platform for gas and power, established in the late 1990s. Market manipulation, false reporting and wash trading brought Enron EOL to a rather quick demise.

Many-to-many platforms are a given for most traded assets such as stocks, bonds, derivatives, commodities, currencies, etc. Multitudes of both sellers and buyers of an asset come together on an exchange, which will charge transaction fees for its service. For certain markets, a one-to-many platform is appropriate. An example is the auction market for art. A single work of art - a one and only Picasso painting, e.g. - would be put up for auction by Sotheby's or Christie's to many bidders. Although an auction house may not technically first purchase an asset from the owner to remarket, it often contractually guarantees a certain price to the owner should the last bid price at the auction fail to meet the reservation price.