Savings and money market

A money market account is a higher-yield savings product with tiered interest rates and a Regulation D-style cap on monthly withdrawals (typically six). The savings sub-module under /banking/money-market/* covers account creation, deposits, withdrawals, sweep configuration, and the cron jobs that accrue and pay interest.

Accounts

Create

{
  "holderId": "holder_abc",
  "productId": "default",
  "linkedAccountId": "acc_checking_abc",
  "initialDeposit": 5000.00
}

Creates a money market account linked to a regular bank account for funding. The linked account is where deposits are pulled from and where interest is paid (or where withdrawals land).

Read

The latter returns all money market accounts for a holder.

Deposits and withdrawals

Deposit

{
  "amount": 1000.00,
  "source": {
    "type": "internal_transfer",
    "accountId": "acc_checking_abc",
    "description": "Monthly savings contribution"
  }
}

Pulls funds from the linked checking account via internal transfer and credits the money market account. Posts a balanced journal entry: debit checking, credit money market.

Withdraw

{
  "amount": 500.00,
  "destination": {
    "type": "internal_transfer",
    "accountId": "acc_checking_abc",
    "description": "Withdrawal to checking"
  }
}

Increments the monthly withdrawal counter on the account. After six withdrawals in a calendar month (configurable per product), further withdrawals are rejected until the counter resets on the 1st.

Auto-sweep

Sweep moves excess balance between checking and money market on a schedule. Useful for keeping working capital in a high-yield account while preserving a target balance for day-to-day spending.

{
  "sourceAccountId": "acc_checking_abc",
  "targetBalance": 5000.00,
  "sweepThreshold": 1000.00,
  "sweepFrequency": "weekly"
}

The actual sweep runs as a scheduled job (typically nightly). The endpoint configures the rule; execution happens on cadence.

Rate tiers

Money market rates are tiered by balance — higher balances earn higher APY.

Create a tier

{
  "productId": "default",
  "minBalance": 0,
  "maxBalance": 9999.99,
  "apy": 3.5
}

Add tiers in increasing balance brackets. The platform picks the right tier per account at accrual time based on the average daily balance for the period.

Get tiers

?productId=default. Returns the configured tier ladder.

Interest accrual

Interest accrues daily and pays monthly. Two cron endpoints drive this:

Run daily — typically at midnight UTC. Computes one day's interest at the account's current tier rate against current balance, posts an accrual entry to the ledger, and adds to the account's accrued-interest counter.

Run monthly — typically on the 1st. Capitalises accrued interest into the balance, posts the corresponding journal entry, and resets the accrued counter.

Run monthly. Resets each account's withdrawal counter to zero so the Reg D-style cap restarts.

These are admin endpoints — schedule them externally (cron, GitHub Actions, k8s CronJob) or via Automation. The platform does not invoke them on a built-in clock.

Stats

Aggregate totals across the org: account count, total balance, average APY, total interest paid YTD.

Standalone savings accounts

The plain savings and business_savings account types from the Accounts module are simpler — no tiered rates, no auto-sweep, no monthly withdrawal cap by default. Use those for basic savings products and the money market endpoints when you need yield tiers and sweep automation.