California Code, Code of Civil Procedure - CCP § 410.40

Any person may maintain an action or proceeding in a court of this state against a foreign corporation or nonresident person where the action or proceeding arises out of or relates to any contract, agreement, or undertaking for which a choice of California law has been made in whole or in part by the parties thereto and which (a) is a contract, agreement, or undertaking, contingent or otherwise, relating to a transaction involving in the aggregate not less than one million dollars ($1,000,000), and (b) contains a provision or provisions under which the foreign corporation or nonresident agrees to submit to the jurisdiction of the courts of this state.

This section applies to contracts, agreements, and undertakings entered into before, on, or after its effective date;  it shall be fully retroactive. Contracts, agreements, and undertakings selecting California law entered into before the effective date of this section shall be valid, enforceable, and effective as if this section had been in effect on the date they were entered into;  and actions and proceedings commencing in a court of this state before the effective date of this section may be maintained as if this section were in effect on the date they were commenced.