"Vinculados" are related parties.

Both Barron's Dictionary of Accounting Terms and Barron's Accounting Handbook define "Related Party Transactions" as transcribed verbatim:

RELATED PARTY TRANSACTION; an interaction between two parties, one of whom can exercise control or significant influence over operating policies of the other. A "special relatinship" may exist, for example, between a business enterprise and its principal owners. In related party situations, the following footnote disclosures are required: (1) nature of the relationship; (2) description of the transaction including amounts; (3) amounts due from or to related parties at year-end; (4) the effects of any change in terms; and (5) manner of settlement. Even though no transactions occurred between related parties in the current year, disclosure of the nature of the control relationship is still required.

--------------------------------------------------
Note added at 1 hr (2007-12-13 22:03:18 GMT)
--------------------------------------------------

RELATED PARTY TRANSACTIONS:
1.160: SFAS No. 57, Related Party Disclosures, specifies the nature of information which should be disclosed in financial statements about related party transactions. Examples of related party disclosures follow:
Reference:
Accounting Trends & Techniques - 2007 / 61st Edition
ATT-SEC 1.160 - Page 120
Published annually by the AICPA

Captions or headings that appear in the secton of RELATED PARTY TRANSACTIONS of Accounting Trends & Techniques - 2007

Sale of Receivables to Subsidiary
Transaction Between Reporting Entity and Investee
Transaction between Reporting Entity and Major Stockholder
Transaction between Reporting Entity and Officer/Director
Transaction Between Reporting Entity and Variable Interest Entity



--------------------------------------------------
Note added at 1 hr (2007-12-13 22:14:39 GMT)
--------------------------------------------------

There are two elements that have become very important in related party transactions and balances. They are TRANSFER PRICING AND ARM'S LENGTH TRANSACTIONS

Following is the definition given by Barron's Accounting Handbook for Transfer Pricing:

Transfer Pricing: deciding on the price of goods or services that are exchanged between various divisions of a decentralized organization. A major goal of transfer pricing is to enable divisions that exchange goods or services to act as independent businesses. Various transfer pricing schemes are available, such as MARKET PRICE, COST-BASED PRICE, or NEGOTIATED PRICE. Unfortunately, there is no single transfer price that will please everybody - that is, top management, the selling division, and the buying division. Usually the best transfer price is the outside market price less costs saved by dealing within the company (e.g., transportation costs, advertising, salesperson salaries). If the two division managers - buying division and selling division - can not agree on a price, one will be arbitrated by upper management. When an outside market price is not available, "budgeted" cost plus profit markup may be used so that the cost efficiencies at the selling division are still maintained.

Following is the definition given by Barron's Accounting Handbook for Arm's Length Transaction:

Arm's Length Transaction: one entered into by unrelated parties, each acting in their own best interest. It is assumed that in this type of transaction, the prices used are the fair market values of the property or services being transferred in the transaction.


--------------------------------------------------
Note added at 1 hr (2007-12-13 22:18:23 GMT)
--------------------------------------------------

It should be noted that tax legislation of more and more countries are making it legally binding for a company to have an annual "transfer pricing study" performed to assure that related party transactions are carried out at the same prices or considerations agreed upon in arm's length transactions. This study is required in Mexico where I live and work. See ártículos 215 and 216 of Mexico's Ley del Impuesto Sobre la Renta (LISR).

On a personal note, Grant Thornton Mexico often sends me "transfer pricing studies" to be translated into English.

Hope all of the above helps.

--------------------------------------------------
Note added at 1 hr (2007-12-13 22:21:38 GMT)
--------------------------------------------------

Silvana Debonis's Dictionary has "Empresas Relacionadas" and "Empresas Vinculcadas" listed as "Related Parties".