Do department stores escheat to the state money from unclaimed gift
certificates or to they keep it as additional profit?  Please let me
know the reference for any answer

Dear phoebeinbrazil-ga 
This is not a straight forward question to answer, for it depends on
which State and whether their Escheat Law applies, or if the gift
certificate is adjudged to be intangible property. Also, if an
expiration date is present or required.
For instance - 
Alaska: A gift certificate that expires before it is used escheats to
the state ? period 5 years
Arkansas: Gift certificates are not included in the definition of
intangible property.
Maryland: Gift certificates are specifically excluded from the
definition of personal property subject to escheat.
Minnesota:. Three years for gift certificates. Minnesota law appears
unsettled regarding whether an expired gift certificate would escheat
to the state.

For a guide to the various States? Escheat Laws visit 
http://www.usegiftcertificates.org/escheatstates.html

As the writer in the source below states:
"There is no easy, uniform answer to questions of escheat. First and
foremost, gift certificate issuers must determine which state?s
escheat law might apply. Thus, issuers must be aware of the lurking
jurisdictional issues and resolve each factual situation as it arises.
Once an issuer has made this determination, it may be able to claim
that, under that state?s law, a gift certificate that expires before
it is used does not escheat to the state (or, that the value of the
property that could escheat to the state is zero)."

This is from a detailed discussion on the law and gift certificates
http://www.usegiftcertificates.org/escheatlaws.html
http://www.usegiftcertificates.org/articles/ESCHEAT%20ARTICLE%20091503.pdf

This is an article from California where a law passed in 1996 to
protect the consumer by stopping the printing of expiry dates on gift
certificates has actually meant the money stays with the stores.
http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2001/01/03/MNB179904.DTL

More information from the Incentive Gift Certificate Council
http://www.usegiftcertificates.org/


I hope this answers your question. If it does not, or the answer is
unclear, then please ask for clarification of this research before
rating the answer. I shall respond to the clarification request as
soon as I receive it.
Thank you
answerfinder


"gift certificates" unused "property of"
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=%22gift+certificates%22+unused+%22property+of%22

I didn't get around to reading this answer until today but find it very helpful.