Cash Flow Priorities tell the simulation where to put your extra money. It's the surplus income left over after expenses each year. The list lives on the Cash Flow tab in Inputs. With priorities, you control the order and amount; without them, the engine routes everything to your brokerage account (see "What happens to the leftover" below).

What a priority is

A priority is a rule that says "before splitting surplus across the rest of the portfolio, contribute to this account first, in this way." Each priority has:

• Account - which account receives the contribution.
• Mode - Maximize Contribution (all leftover income), % of Remaining Income, Specific Amount (fixed dollars per year), or Build to Target Balance.
• Time range - start and end milestones (Start of Plan, At Retirement, End of Plan, or a specific year offset).
• Must be funded - when checked, the priority is funded even if the engine has to withdraw from other accounts to do it.
• Linked Job - for 401k / 403b / 457(b) goals, link to a Job adjustment so the contribution is treated as a payroll deferral that reduces taxable income and unlocks employer match.

The order surplus flows through

Each simulated year, after income arrives and base expenses are subtracted, the engine walks the priority list top-to-bottom:

1. Each priority either takes a fixed amount, a percentage of remaining surplus, builds toward a target balance, or absorbs everything left (Maximize Contribution).
2. If a priority can't be fully funded, the engine moves on to the next one.
3. Anything still remaining after the last priority is handled by the Save-vs-Spend selector at the bottom of the Cash Flow tab (see the next section).

What happens to the leftover

The dropdown at the bottom of the Cash Flow tab decides what happens to any surplus the priorities above don't claim. New simulations start with this toggle unset — you'll see a "Choose one..." placeholder and Run is blocked until you pick one of the two modes. There's no silent default; the choice is significant enough that we want it to be an explicit decision.

• Save excess cashflow (shown in green) - the leftover lands in your brokerage account. If you have more than one brokerage, a secondary picker lets you choose which one; otherwise the engine uses the only brokerage you have. This is the simulation's catch-all for unallocated cash and is why every plan needs at least one brokerage account.
• Spend excess cashflow (shown in red) - the leftover is treated as discretionary spending and drops out of the simulation. Use this when you want to model "I'd just spend any extra money rather than save it" - a useful baseline for figuring out how much portfolio you actually need rather than how big it could grow if you kept investing every dollar of surplus.

In Spend mode, the discretionary amount appears as a red sink on the Proof view's Sankey and a "Discretionary Spending" row on the year-detail card. Fixed priorities (Must be funded) still fire regardless of the mode - they represent contributions the engine treats as non-negotiable.

Where to set them

The list lives on the Cash Flow tab in Inputs. Drag rows to reorder. Click any row to edit its mode, amount, or time range. The plus button at the bottom of the list adds a new priority. Below the list is the Save-vs-Spend selector covered above. Empty priority list + Save mode = the entire surplus lands in your brokerage account.