I'm in the United States on a B-1 business visitor visa for six months to evaluate potential investments. My goal is to get an E-2 treaty investor visa to allow me to be in the U.S. to run the business I purchase or establish. Can I stay here and get the E-2 visa, or do I need to go back and get the visa in my home country?
Initially, the answer to your question will be the same whether you eventually apply for an E-2 investor visa or an E-1 trader visa. See the following two Nolo articles for more information: "E-1 Visa for Treaty Traders in the U.S.: Who Qualifies?" and "E-2 Visa for Treaty Investors in the U.S.: Who Qualifies?"
Because you are in the U.S. on a B-1 visa, rather than as a visitor under the Visa Waiver Program/ESTA, you can submit an application to U.S. Citizenship and Immigration Services (USCIS) to change your immigration status from B-1 to E-1 or E-2. (Visitors in the U.S. on the Visa Waiver Program are not eligible to change status from within the country.) But think twice before you do that. Keep reading to learn why.
Although USCIS has authority to approve applications for a change from one immigration status to another, the E visa truly falls within the domain of the U.S. State Department, through its embassies and consulates around the world. When you apply to change your status with USCIS from within the U.S., you're only changing your status (i.e. the terms and length of your permission to remain here) and not getting a new visa (i.e. the document that allows you to seek to enter the country). The next time you travel outside the U.S., therefore, you would need to get an E visa from the U.S. consulate in your home country.
While the USCIS approval of your change of status application certainly is persuasive, it does not require the U.S. consulate to issue you an E visa. Rather, you would then need to submit a complete registration application, which likely would be similar to your change of status application. The U.S. consulate will make its own determination concerning whether you meet the requirements for the E visa. Some consulates take just a few weeks to review the application, while others take several months.
The fact that the U.S. will make its own determination on its own time when you apply for a visa leads most E visa applicants simply to apply at the U.S. consulate in their home country, even if they were eligible to change status in the United States. Most people will need to travel outside the U.S. at some point, and it's often best to know from the very beginning whether you'll get the visa. Imagine changing status in the U.S. and then having your visa application denied at the U.S. consulate six months later during a "quick trip" home. Therefore, the recommended approach in your case will be to plan on a trip home to get your visa before getting too far along with your new venture in the United States.