If you are applying for U.S. permanent residence (a “green card”) based on certain family relationships or through an employer sponsor, then you need to understand the Visa Bulletin and how it affects the timing of your case. Linked here is a flyer explaining how the system works. In brief:
The U.S. can only approve a certain number of green cards each year (through adjustment of status or an immigrant visa application). The limit is 226,000 for family-based preference category immigrants and 140,000 for employment-based preference category immigrants.
The Family- and Employment-based numbers are broken up into multiple sub-categories.
Citizens of a single country can use only a certain percentage of the numbers in any category (actually based on country of birth, not necessarily citizenship).
There are certain countries that reach this limit, so people born in those countries who are going through the permanent residence process then have backlogs before they can file their final application and obtain the green card. The Department of State establishes cut-off dates determining who can file and complete the final step in their permanent residence process.
This results in the Visa Bulletin, which the Department of State updates monthly with new cut-off dates.
This October, the Visa Bulletin took a huge jump forward, particularly for employment-based cases, allowing large numbers of applicants to file in a single month.
Check out this flyer for more details.