Legal Question in Investment Law in California

Maybe, but probably not. You have given just enough facts to allow a lawyer to make some further assumptions about the situation (which may be incorrect, of course).

First, you don't say that the envelope was addressed to you; only that the checks are "in you name." To whom was the envelope addressed, your parent or guardian? Even if it were addressed to you, the post office is permitted to deliver it to another adult living at the same address, as your ostensible agent.

Next, have you seen the checks so as to know exactly to whom they are payable? The checks may be payable to your parent or guardian as your custodian. Depending upon the state of residence of the donor and the law in effect in that state at the time a gifts (or transfers) to minors account was set up, the custodianship may continue beyond the date you turn eighteen.

I know there are many instances of parents grabbing and spending their kids' custodial funds for things that have nothing to do with the kids' welfare and benefit. That might be what's going on here. Very possibly, however, the person who has commandeered "your" checks has done so with the full blessing of the applicable law.

With more facts, I might be able to give you a more precise answer. Those facts would include whether this is proceeds from a UTMA or UGMA gift or transfer; your age; the date at which the transfer was made; the state of residence of the donor or transferor, and any instructions to the custodians from the donor or transferor. It might also be useful to know whether the custodian (assuming these are custodial funds) seems to be using the funds for your college education (for example) or is spending them on expensive whiskey.

One thing you might do is if you know the source of the funds and it is a relative who is living and still competent, ask what they had in mind for you when they created the UGMA or UTMA account.

(UGMA = Uniform Gifts to Minors Act; UTMA = Uniform Transfers to Minors Act. UGMA was older law and was replaced by UTMA in most states about 20-30 years ago).

I just noticed that you said "UPS" (United Parcel Service) and I answered as though you had said "USPS" (United States Postal Service). If indeed you meant the items arrived via United Parcel Service, I'm reasonably sure the answer would be about the same, however, since UPS doesn't provide "certified mail" service, I think you meant USPS.