The "Build Now Act of 2025" proposes to incentivize increased housing supply by modifying the allocation of Community Development Block Grant (CDBG) funds. This legislation directs the Secretary of Housing and Urban Development to adjust CDBG allocations for eligible metropolitan cities and urban counties. These adjustments will be based on their measured housing growth improvement rate , which compares current annual housing unit growth to prior growth. Under the bill, recipients whose improvement rate is at or above the median for all eligible recipients, or those designated as extremely high-growth recipients (with a current annual growth rate of 4% or more), will receive a bonus amount in addition to their regular CDBG allocation. This bonus is funded by reductions from other recipients. Conversely, eligible recipients with a housing growth improvement rate below the median will face a 10 percent decrease in their CDBG allocation. However, certain covered recipients are deemed "ineligible" for these adjustments, including those with low median rents or home values, high rental vacancy rates, recent major disaster declarations, or a lack of legal authority to update zoning ordinances, thereby protecting communities facing specific challenges. The Secretary is required to publish an annual report detailing these rates and adjustments, and to provide guidance on best practices for reducing regulatory barriers to housing. These CDBG allocation adjustments are set to take effect in the third full fiscal year after enactment and will remain in force through fiscal year 2043.