How do recurring investments work at your broker?

On each scheduled date the broker places a buy for a set dollar amount rather than a set number of shares. Robinhood describes it this way on its help page: recurring investments only support dollar-based orders, so the number of shares depends on the price that day. Its own example is a $10 weekly buy of a $40 stock, which comes out to 0.25 shares.

That is dollar-cost averaging, which the SEC's Investor.gov glossary defines as investing money in equal portions at regular intervals regardless of the ups and downs in the market. The same amount buys more shares when the price is low and fewer when it is high. FINRA's investor page on the strategy adds the other side: spreading money out lowers risk but often produces lower returns than investing a lump sum, especially over long periods. A recurring plan is mostly a way to invest money as it is earned, rather than a way to beat a lump sum.

The order itself is ordinary. It goes into the market during trading hours, fills at the price available, and shows up in your positions like any buy you placed by hand. What makes it recurring is only the schedule, and the question of where the money comes from.

This is the setting that matters most, and brokers handle it in three different ways.

The broker pulls from your bank on the day

Robinhood lets a recurring investment pay from buying power or from a linked bank account. When the bank is the source, its help page says the order uses your instant deposits limit while the transfer processes, and if you do not have instant deposits available, the order is placed after the transfer completes, which can take up to five business days. Fidelity's recurring investments page says plans can be paid from your Fidelity core (cash) position or from a linked bank account.

The transfer and the buy are separate settings

Public splits them. Its help center describes recurring deposits as moving cash into an account on a daily, weekly, biweekly or monthly schedule without buying anything, and says a recurring deposit is not required to start an Investment Plan, whose funding is chosen when the plan is created. The first recurring deposit lands on the next business day after it is set up.

The plan only spends cash that is already there

This is how a recurring investment in Walnut works, and it answers the most common question about it. Walnut does not take money from your bank. There is no way for it to: it connects to your brokerage account, not your bank, and it has no funding access. The cash has to arrive first, put there by you or by your broker's own recurring deposit. On the scheduled day Walnut reads the account's cash balance, and only if the full amount is there does it place the buys.

The practical consequence is timing. If your broker's automatic deposit pulls $200 from your bank on the 28th, a plan set for the 1st has a few days of margin for the transfer to settle. A plan set for the same day as the deposit is relying on the transfer landing before the check runs.

Every recurring plan eventually meets a month where the money is short. What happens next varies more than anything else on this page.

At Robinhood, the help page lists the outcomes. An order is skipped when there is not enough buying power, the bank transfer fails, or a technical error occurs. A plan is paused when a bank transfer is reversed, which the page says sometimes happens when the bank account has insufficient funds, or the bank account is unlinked. If you pay with buying power, you can add a backup payment method so the plan keeps going when buying power runs out.

In Walnut, a short balance produces a skip rather than a partial buy. The plan does not spend whatever is there and call the period done. Instead:

• The skip is recorded with the cash it found, and the period is held open.
• The plan tries again on each weekday run for up to five days after the scheduled date. A deposit that lands on day three gets invested on day three.
• You get a notification in the app, and a short-cash skip is also emailed, with the last date it will retry.
• If the cash never arrives inside that window, the period is marked missed and the plan moves on to its next date. That gets its own notification, so a lost contribution is never silent.

Walnut also refuses to borrow. It reads the account's cash figure rather than its buying power, because buying power on a margin account includes money the broker would lend you, and spending against it would turn a monthly contribution into a leveraged one. Buying power is only used when a broker reports no cash figure at all.

A subtle design question is what a plan does after a gap. Suppose a plan was paused for four months, or a broker connection dropped for a week. A naive scheduler would notice four unpaid months and buy four times on the first day back.

Walnut does not do that. A missed period stays missed, and after any gap the plan resumes at its next scheduled date with a single buy. Missed periods are not made up later. If you want to put the skipped money to work, a one-time investment into the same basket does it deliberately.

The opposite failure, buying twice, is guarded against even harder. Each period can be invested exactly once: the order is keyed to the plan and the period rather than the calendar day, so if the same check runs twice, the second one replays the first instead of buying again. Retries are only safe because of that.

Two scheduling details round this out. Brokers move a buy that falls on a weekend or market holiday: Fidelity says the order executes on the next trading day, and Robinhood says it moves to the next trading day. Walnut runs on weekdays, and an order placed on a market holiday waits at the broker until it fills. A monthly plan set for the 31st buys on February 28 and then goes back to March 31, rather than drifting to the 28th for good.

Dollar-based plans depend on fractional shares, and every broker sets a floor on how small a fractional order can be. Public's help center says stock buys through fractional trading have a $5 minimum. Fidelity's recurring investments page allows between $1 and $100,000 per plan for stocks, ETFs and baskets, and between $10 and $100,000 for mutual funds.

For a single fund that floor rarely matters. For a basket it does, because the plan amount is split across every holding, and the smallest slice has to clear the minimum. The number that decides it is the smallest weight in the basket, not how many holdings it has.

The arithmetic is the floor divided by the smallest weight. A $100 monthly plan into a basket whose smallest holding is 10% sends $10 to that holding, which clears Public's $5 minimum. Cut the same holding to 4% and the slice becomes $4, which a broker with a $5 floor rejects. Walnut works this out when the plan is set up and shows the smallest amount that works, so the problem appears on the setup screen rather than as a rejected order a month later. A Robinhood Agentic account has a $1 floor per order, and Walnut plans run from $5 to $100,000 a period.

Broker plans and Walnut plans solve slightly different problems. A broker plan is built around one account and, usually, a short list of symbols. A Walnut plan is built around a basket with target weights.

The trade-off is convenience. A broker plan that pulls from your bank needs no second setting. A Walnut plan needs the money to be at the broker first, which usually means pairing it with a recurring deposit at the broker. In return it can buy a basket of names to your weights, across whichever supported broker holds the cash.

Walnut places recurring buys at Public and in a Robinhood Agentic account (the main Robinhood account stays view-only to outside apps), and also at E*Trade, tastytrade, Webull (US and Canada), moomoo, Questrade, Wealthsimple, Trading 212 and Stake (Australia). Other brokers, including Fidelity, Schwab, Vanguard and Interactive Brokers, are read in full but do not take orders through Walnut, so a plan on one of those accounts is skipped as read-only.

1. Connect a brokerage that can take orders

Connect your account from the brokerage page. Walnut shows which connections can place trades and which are read-only. If you are opening a new account to trade with Walnut, Public and Robinhood are the two it suggests.

2. Pick or build a basket

A basket is a list of holdings with target weights. You can build one yourself, start from a playbook on the Ideas shelf, or ask the assistant to draft one from a theme.

3. Open Invest and choose Recurring

In the Invest dialog, enter an amount, choose Recurring, and pick weekly, every two weeks, or monthly on a day of the month. Walnut shows the smallest amount that works for that basket's weights.

4. Schedule the cash to arrive first

Set up a recurring deposit at your broker that lands a few days before the plan date. Walnut does not move this money; your broker does.

5. Press Test

The Test button runs every check the real run would, against your live account, including the cash balance and whether the account can trade. It places no order and does not use up a period.

6. Watch notifications

Every buy and every skip appears in notifications. You can pause, resume or cancel the plan at any time from the same dialog.

• Scheduling the buy on the same day as the deposit. A transfer that has not settled reads as no cash. A gap of a few days avoids most skips.
• Assuming the app moves money. Plans that only spend broker cash depend on a separate deposit. Without one, the first month or two run on whatever cash was left over and then start skipping.
• A tiny weight in a small plan. A 3% holding in a $100 plan is a $3 slice, under Public's $5 floor. Raise the amount or the weight.
• Counting on margin to cover a short month. Walnut deliberately reads cash, not buying power, so a margin balance does not rescue a skipped buy.
• Expecting a catch-up after a pause. Resuming a plan restarts it at the next date. Skipped months stay skipped unless you invest them by hand.
• Setting a plan on a read-only connection. Brokers that do not take orders through Walnut are tracked in full, but a plan on one of them will skip every period.

Robinhood's funding options, skip and pause rules, bank-transfer delay and holiday handling are from its help page About recurring investments and orders. Fidelity's minimums, funding sources and non-trading-day rule are from Fidelity recurring investments. Public's $5 fractional minimum is from What is the minimum amount to invest in stock, and its deposit and plan settings from How to set up and manage recurring deposits and Does Public offer recurring investments. The definition of dollar-cost averaging is from the SEC's Investor.gov glossary, and its limits from FINRA. More on the Walnut feature is on the recurring investments page, and the concept is covered in What is dollar-cost averaging? Walnut is an AI investing app, not a registered investment adviser, and this guide is educational rather than personalized advice.