How would an EB-5 application affect an H-1B extension?

You may need to indicate if an immigrant petition has been filed. The I-526 is an immigrant petition. H-1B does allow for dual intent in regard to immigrant/nonimmigrant intent.

Because H-1B is a dual intent visa that allows you to apply for permanent residence in the United States in the future if all requirements have been met, a pending EB-5 application should not affect your H-1B extension. If you have filed an I-526 petition, then you should disclose this information when filing the H-1B extension. If you have not filed the I-526 petition when filing your H-1B extension, then you need not disclose your intent to file the I-526 petition in the future.

You apply for your H-1B status first. Once you receive that, then make your EB-5 application.

One does not have anything to do with the other. With an approved H-1B petition though, you will be able to enter the country even while the EB-5 application is pending as an H-1B visa is a dual intent visa.

H-1B is a duel intent visa. Your immigration petition will not affect your H-1B petition. Actually, it is safer to maintain a nonimmigrant status while your immigration petition is pending.

Your EB-5 application will not affect your H-1B extension application, for H-1B allows you to have immigrant intent. The USCIS can use your A number to track all your applications. It will not be a problem.

While you must disclose that you have an EB-5 filing when extending the H-1B, it will not adversely impact the extension as the H-1B is a dual intent visa.

H-1B is a dual intent visa category and having an EB-5 case does not affect your extension application or status. If you have not filed your EB-5 case, there is no reason to tell them that you will be doing so. In fact, there is no place in the extension application where you could tell them what you may be considering. If you have already filed the I-526 when you are filing your extension, then you should note that.