Appropriations law decides what the government may buy from you, without regard for whether the customer wants it.
Read the colors first
Five common colors, five legal purposes
Congress appropriates money in categories founders call colors: RDT&E for development, procurement for production buys, O&M for operations and services, MILCON for construction, and MILPERS for people. Each carries a legal purpose and a period of availability; these accounts are generally available for one, two, three, or five years as shown. Charging the wrong appropriation violates the Purpose Statute and can also trigger the Antideficiency Act if the proper account lacks enough funds. Customer enthusiasm cannot cure either problem.
PPBE works years ahead
The PPBE cycle programs money well before it is spent. If your capability has no budget line today, deliberate funding usually begins in a future programming cycle. Current-year wins come from funds already available for your use: existing lines with headroom, lawful reprogramming actions, or innovation funds built to move faster. Meanwhile, work with a program office to plant funding in the out-years. Founders who plan revenue against the fiscal calendar stop being surprised by it.
Wanting it and buying it are separate authorities
The most common founder failure in this market: an end user who loves the product, connected to a budget holder without funds legally available for the buy. O&M generally funds operating expenses and lower-cost items; procurement generally funds investments and centrally managed items; RDT&E funds development rather than routine production. Before you commit to a pilot, ask which appropriation pays for production. Silence in response predicts the pilot's afterlife with uncomfortable accuracy.
Demand signals, published annually
R-1 and P-1 exhibits and their justification books name programs, dollar amounts, and out-year plans in public documents published every budget cycle. Founders who read them stop guessing. A budget line growing forty percent across the FYDP is a demand signal worth investigating, not a market guarantee. A flat line names the strategic latency you may have to out-wait or route around. Every serious defense company has someone who reads the J-books the week they drop.
Structure converts intent into contract
SBIR, OTA, and Phase III authorities do not convert colors or relax fiscal law. They provide contracting paths for funds already available for the work. Match the scope, contract structure, and appropriation: operating services may fit O&M, development may fit RDT&E, and production may fit procurement through a Phase III award when the work derives from prior SBIR/STTR effort. The founders who win this market sell the contract structure along with the product.
DoD Financial Management Regulation, Volume 3, Chapter 13 for periods of availability; GAO Principles of Federal Appropriations Law for purpose, time, and amount; SBA SBIR/STTR Policy Directive for Phase III.
Merge Combinator co-founds defense ventures with champions who own the problem, and with the color-of-money map drawn before the first pilot conversation. Bring your capability; we bring the budget mechanics.