This article investigates the general characteristics and developments of the MARC format for holdings data. It also analyzes the record structure, content designation, and the content of it, mainly based on USMARC and KORMARC formats. Structure and content designation of them are almost same with those of the bibliographic and authority formats. The data fields divided into functional blocks based on their functions, but only 0XX, 5XX, 8XX fields are used in the holdings formats. Record contents of the data in the 008 fields include more elements related to the holdings and acquisition information. Variable fields can be grouped into several blocks, including those for numbers and codes; for notes fields, for location , and for holdings data. Holdings data fields include caption and pattern fields, enumeration and chronology fields, textual holdings fields, and item information fields. This article analyzes the content in each data fields in detail.