Period after abbreviation (Ltd) - English Language & Usage

This is a matter of using a proper name with a style of punctuation. Your first guide should be the usage preferred by the named entity itself. Use whatever Acme Brocade, Decoration, and Costumers, Limited calls itself, whether that be

ABDCL
ABDC, Ltd
ABDC, Ltd.

or other combination of their choosing.

Style guides differ. Oxford Dictionaries says that initialisms like ABDC and NASA don't use periods and neither do abbreviations using the the first and last letter of the word abbreviated. That means

Mr Dr Ltd and US

They do note some American exceptions (e.g, U.S.). The Chicago Manual of Style, however, puts the period after Mr. and Dr.

Chicago recommends dropping an abbreviating period at the end of a sentence and dropping all punctuation except terminal (i.e., sentence ending) punctuation before a closing parenthesis. If the company or your style guide required a period -- Ltd. -- then

XYX signed the contract with ABDC, Ltd.
XYX signed the contract
with ABDC, Ltd. (ABCL).
XYX signed the contract with the company
(ABDC Ltd).