This is from a flyer that CA puts out for foreign corporations an other business entities (foreign simply meaning incorporated in another state, and doing business in California) - I'll give you the link:
Corporation Franchise TaxYou are responsible for the corporation franchise tax if yourcorporation or limited liability company treated as acorporation is doing business in California. Doing business inCalifornia is defined as actively engaging in any transactionin California for the purpose of financial gain or profit.Foreign corporations that are general partners of partnershipsor members of limited liability companies (treated aspartnerships for tax purposes) doing business in Californiaare also responsible for the corporation franchise tax.
Further, foreign corporations should be aware of California’s worldwide combined reporting method of taxation. In contrast to
the arm’s-length, separate accounting method employed by the U.S. federal government, California’s system calculates abusiness enterprise’s income taxes by treating as a single enterprise all of the worldwide affiliates of a multinationalbusiness group that are engaged in a so-called “unitary” business. Once the worldwide income is determined, it is dividedbetween California and the rest of the world on the basis of a three-factor apportionment formula of property, payroll,and sales.
This document will answer all of your questions:
A foreign corporation (a corporation, association or other legal entity that is not incorporated in California) that conducts intrastate business inCalifornia must obtain a Certificate of Qualification to do business in California. Any corporation, whether it is a Delaware, Swedish, Texas, or Mexican corporation that “does business” or “derives income from sources within California” is generally subject to California’s tax laws.
There are credits in NY for taxes paid to other states, so you will not be COMPLETELY subjected to DOUBLE taxation, but the net effect will be that the taxes will be effetcively taxed at the higher of the two.
Hope this helps
Let me know if you have further questions