As the world keeps shrinking, partners from different countries are forming lots of companies.

This is not only evident in mega-mergers by multinationals, but also with startups, especially in the computer industry.

But often overlooked in the launching of these ventures is the visa status of foreign partners or employees. Lack of planning can severely hinder the long-term prospects for success.

During the first phase of starting a business, when deals are negotiated, office space secured and the entity organized, there is no requirement that a foreign national have a visa authorizing employment.

All those activities are permissible when someone is admitted to this country with a business visitor/tourist (B-1/B-2) visa, or under the visa waiver program, which allows nationals of specific countries to enter the U.S. without first applying at a U.S. embassy.

A foreign national holding a business visitor visa is normally allowed to remain here for six months. His or her stay may be extended for six months, if warranted.

Someone admitted under the visa waiver program can remain in the U.S. for three months, with no extensions granted. However, if the person leaves and then returns, he or she can remain an additional three months.

Startups primarily utilize three types of long-term visas for partners and employees. When applying, both the company and individual must meet certain requirements. Here’s a look at each category:

– The specialty occupation visa (H-1B) is available to workers who will perform temporary services in a certain field. Generally, professionals with a bachelor’s degree in a field related to the employment position, or who have years of progressively responsible experience in that field, can qualify for this visa.

It’s a good choice when the new venture involves a small initial investment. However, the firm must prove it has a good chance to survive by providing a business plan, contracts for goods or services, invoices, deposits for future work, etc.The maximum period of stay for holders of these visas is six years.

– The intra-company transferee visa (L-1) is ideal for an international organization entering the U.S. marketplace.

To qualify, an overseas parent or affiliate company of the U.S. firm must have employed the person for at least one year within the past three as an executive, manager or specialized knowledge employee. The person must work at the U.S. firm in a commensurate position.

For a startup to qualify, it must be at least 50 percent owned and controlled by the parent or affiliate of the U.S. enterprise.

L-1 visas for startups are normally issued for a year. To gain an extension, it’s vital for the company to generate revenue and employ several U.S. workers. Such visas are good for a maximum of seven years. Employees with specialized knowledge are allowed to remain for no more than five years.

– Treaty trader/investor visas (E-1/E-2) are granted to citizens of countries signatory to certain types of commercial treaties with the United States. For partners or employees of a U.S. company to qualify, it must be a commercial enterprise at least 50 percent owned by a foreign firm or by a national of the signatory country.

The company must be engaged in substantial trade, principally between the foreign nation and this country, or make a substantial investment in the United States.

For trade in goods or services to be considered substantial, it must be regular and systematic. For an investment to be considered substantial, it must be enough for the company to commence operations in the U.S. marketplace. For larger firms, there are special rules governing the amount of investment required.

To qualify, individuals must be nationals of the same signatory country as the company’s owner(s). The applicant must have experience working as an executive or manager, or be an employee with specialized or essential skills and/or knowledge of the product, marketing, strategies, international system of operation, or other knowledge not readily available in the U.S. job market.

Treaty visas are generally issued for five years. There is no limit on the number of times they can be renewed, as long as all the essential elements of the application remain the same.

Brandon Valvo is the founder of Valvo & Associates Inc., a multinational law firm in Los Angeles dealing solely in U.S. immigration and nationality law.

Entrepreneur’s Notebook is a regular column contributed by EC2, The Annenberg Incubator Project, a center for multimedia and electronic communications at the University of Southern California. Contact James Klein at (213) 743-1759 with feedback and topic suggestions.