Personal representatives (executors and administrators) are usually required to obtain a bond as a condition of serving. Probate bonds can be obtained from various bond companies. A couple of main companies handle most of the bonds for San Francisco Probates, and it's very helpful to have a bond company that understands the local requirements. Different counties can have different requirements, so you need to work with someone familiar with the local rules.
The bond is not there to protect the personal representative! It’s there to protect the estate against the mistakes or malfeasance of the personal representative. The primary purpose of the bond is to protect creditors of the estate; people or companies that believe the decedent owed them money. Since the estate is generally liable for the debts of the decedent, and the State of California has an interest in making sure that debts are paid, the law generally requires the personal representative to post a bond.
To obtain a bond from a bond company, the proposed personal representative will have to demonstrate that their own finances are in reasonable shape. The bond company will ask for personal financial information in order to make sure they are making a safe bet in issuing the bond. The bond company will run a credit check and take other steps to make sure the personal representative can handle money before issuing the bond. If the bond company agrees to issue the bond, they prepare a document that gets signed and filed with the court.
What if the proposed personal representative doesn’t qualify for a bond? There are a couple of options: (1) the attorney for the personal representative might agree to serve as a co-signer on the estate’s bank accounts; or (2) the personal representative can request the court to approve the use of a blocked account. A blocked account cannot disburse funds without an order of the court. Obviously, a blocked account can cause delays, but sometimes it’s the only way to solve the problem. A good probate attorney may be able to work out other solutions as well.
Additional Reading - The Probate Process in California - A Summary