The content of the Visa Bulletin, including cutoff dates and indications of current (C) or unavailable (U), determine both whether a pending Application for Adjustment of Status (I-485) case can be approved, as well as when an I-485 can be filed. It also determines whether a visa number is available to any U.S. consulate abroad for immigrant visa processing in a particular category.
The Visa Bulletin is intended to reflect the availability of visas for cases that are pending. Thus, if there is an indication of current, there are enough visa numbers for cases in that category that have been filed and are far enough along in the process to be ready for approval during the particular month for which that bulletin was prepared.
It does not mean that there are enough visa numbers for all cases in that category that may exist either in the queue or that are waiting for cutoff date movement in order to be filed. Since the USCIS ties the filing of I-485 cases to the Visa Bulletin, however, priority date movement has the result of allowing cases to be filed, even if there will not be enough visa numbers available for the particular cases once they are reviewed by the USCIS. Many who filed I-485s during the summer of 2007 have come to understand this concept, as their cases are pending but may not be eligible for approval for a very long time due to a shortage of immigrant visa numbers under the per-country quota limits.
The cutoff dates are set based upon estimates of anticipated demand for visa numbers. Taken into consideration are historical patterns, data regarding cases awaiting interview at the consulates, and reports from the USCIS about their case load. The dates are set in an effort to use all the immigrant visa numbers by the end of the fiscal year, however, efforts are made to avoid having a category become unavailable.http://www.greencardapply.com/news/news08/news08_0523.htm
