California Code, Civil Code - CIV § 3336

The detriment caused by the wrongful conversion of personal property is presumed to be:

First--The value of the property at the time of the conversion, with the interest from that time, or, an amount sufficient to indemnify the party injured for the loss which is the natural, reasonable and proximate result of the wrongful act complained of and which a proper degree of prudence on his part would not have averted; and

Second--A fair compensation for the time and money properly expended in pursuit of the property.