relationships · 10 min read
A Two-Year Experiment Tested Joint and Separate Bank Accounts on Newlyweds
Newlyweds told to open a joint account kept their relationship quality steady for two years. Those kept on separate accounts slipped.
By AmpleGuide Editors · Updated October 2026
In 2013, four business and psychology professors started recruiting engaged and newlywed couples for a project they called the Transition to Marriage Study. None of the couples they enrolled had a joint account, and the team then chose some at random and asked them to open a joint account and live on it for two years.
The paper came out in the Journal of Consumer Research in 2023. Couples sent to a joint account rated their relationship about as highly at the end as they had at the start. Couples told to keep separate accounts declined at the same pace as couples given no instructions at all.
If you’re setting up money with a partner, you’ll want that result, the study’s limits and what each setup does to your money under the law.
Inside the two-year experiment
The study, led by Jenny Olson of Indiana University’s Kelley School of Business, enrolled 230 male-female couples in the United States. Each partner was entering a first marriage, each couple was engaged or had been married less than a year, and none of them had a joint account yet.
The team split the couples three ways. Of the 230, 96 were told to open a joint checking or savings account within a month and stop using their own accounts. Another 66 were told to stay fully separate, while the last 68 got no instructions at all. Partners answered surveys on their own at the start and again at months 3, 6, 9, 12 and 24.
The group with no instructions showed the usual newlywed pattern, a slow drop in how good partners said their relationship was, and the separate group fell at about the same rate.
The joint group didn’t decline.
Most of that gap traced back to what the authors call financial harmony, meaning how happy partners were with the way they handled and talked about money. That score climbed in the joint group while it stayed flat in the other two, and it explained about 75 percent of the difference between the joint group and the others.
If you’ve ever argued over a purchase you learned about late, the authors’ reading will sound familiar. One shared account leaves fewer places to hide a purchase and more reasons to agree on what your money is for.
Why one study doesn’t settle it
Random assignment is what makes this study stronger than earlier surveys, which could only show that happier couples tend to share accounts. It still has soft spots, which the authors name themselves, so weigh them before you treat the result as advice for your own marriage.
The biggest one is dropout, since opening a joint account takes effort. In the joint group, 34 percent of couples answered no survey after the first one, against 12 percent in the separate group and 6 percent in the group with no instructions.
Volunteers are the second soft spot. Of 962 couples who passed the screening, 230 signed up knowing they might have to merge their money, so the sample leaned toward people open to the idea. The data were gathered from 2013 to 2017, in one country, among male-female couples in first marriages.
If you or your partner balk at merging, you’re the kind of couple the study had the least to say about.
The authors also warn that a joint account cuts into each partner’s independence and could raise the risk of control or abuse. Merging, they write, is “unlikely to be the best option for all.”
If a partner uses money to control you, talk to someone before you merge anything. The National Domestic Violence Hotline, at 1-800-799-7233, is free, confidential and open around the clock.
Three ways couples set it up
A fully joint setup puts both your paychecks into accounts you own together, and every bill comes out of them.
Fully separate means each of you keeps your own accounts and you settle shared costs between you, by splitting each bill or taking turns.
The hybrid, often called yours, mine and ours, keeps one joint account for rent, groceries and other shared bills while each of you holds a personal account for everything else.
Where you land may depend on how long you’ve been together. Among people who answered the study’s screening survey, which targeted engaged couples and newlyweds, 43.8 percent kept fully separate accounts, 32.5 percent mixed and 23.6 percent were fully joint. A second survey in 2022 asked 507 married people, together an average of 15 years, and found 52 percent fully joint, 32 percent mixed and 16 percent fully separate.
The hybrid looks like the easy compromise. In that 2022 survey, though, people with a mix of joint and separate accounts looked like the fully separate group on money harmony, shared goals and openness about spending, and only the fully joint group stood out. Asked to imagine a spouse’s $1,000 work bonus, the fully joint group was also the likeliest to call it “our money.”
That survey can’t tell you which came first, the shared account or the closeness, and it carries none of the experiment’s weight.
The hybrid also takes the most upkeep of the three, since someone has to decide how much each of you feeds the shared account. That number goes stale every time one of your paychecks changes.
What each setup means legally
The three setups part ways on five points, and the rules behind them come from the FDIC and from state law, which varies by where you live.
| Fully joint | Hybrid | Fully separate | |
|---|---|---|---|
| Who sees the spending | Both of you see every purchase | Both see shared bills; personal spending stays private | Each of you sees only your own |
| Who can withdraw | Either owner, up to the full balance | Either owner from the joint account | Only the account’s owner |
| FDIC insurance at one bank | $250,000 per co-owner across joint accounts | Joint share, plus $250,000 for each person’s single accounts | $250,000 per person across single accounts |
| If one of you dies | The balance usually goes to the surviving owner | Joint balance goes to the survivor; personal accounts follow a will or named beneficiary | Follows a will, a named beneficiary or probate |
| If one of you owes a court judgment | A creditor can try to reach the joint account | The joint account is exposed; personal accounts depend on state law | Depends on your state, as the California rule below shows |
The FDIC treats joint accounts as their own category, insuring each co-owner’s share up to $250,000 apart from single accounts, but only if every owner has equal rights to withdraw. That means either of you can take out the whole balance.
Who owns the money is a separate question from who can take it out. By default, California’s Probate Code says a joint account belongs to the living owners in proportion to what each put in, and when one owner dies the balance goes to the survivor, whatever your will says.
New York’s Banking Law treats a deposit in two names, payable to either, as a joint tenancy that passes to the survivor.
How far a partner’s debts reach
Debts are where your choice of setup can matter most. In California, under Code of Civil Procedure section 700.160, a creditor with a court judgment against one partner can levy any account in that partner’s name, joint ones included, without going back to court. The bank must then wait 15 days after notice reaches the other owner before it pays out.
The same law lets a creditor levy an account held only in the debtor’s spouse’s name, once it hands the bank a sworn statement that the two are married.
If either of you has a judgment on record, ask a legal aid lawyer which of your accounts a creditor could reach.
Questions that can tilt the choice
No single setup wins for everyone, and the experiment covered only one kind of couple, which may not be yours. These questions help you see where you might lean.
Do your take-home pays differ a lot? In the experiment, a gap between partners’ pay didn’t change the result, but it does change how a 50/50 split feels.
Say one of you takes home $6,000 a month, the other takes home $4,000 and your shared bills come to $4,000. Splitting evenly costs each of you $2,000 and leaves you with $4,000 and $2,000, while splitting by income, 60 percent and 40 percent, means paying $2,400 and $1,600 and keeping $3,600 and $2,400.
Is either of you bringing children, a home or savings from an earlier relationship? A joint balance usually passes to the surviving owner, not to your children from a first marriage, and in California your will can’t redirect it.
Separate accounts with named beneficiaries give you more say over where that money goes.
Does one of you carry old judgments, collections or tax debt? The California rule above shows that a joint account can put both partners’ cash in a creditor’s path.
And how does each of you feel about the other seeing every purchase? Some people find that freeing and others find it tiring, so hear your partner’s answer before anyone opens an account.
A script for the first money talk
Pick a calm evening, well away from the day your rent is due, and take turns answering these out loud.
- “How did money work in the house you grew up in, and what do you want to keep or drop from that?”
- “Which bills feel shared to you, and which feel like yours alone?”
- “How much could one of us spend without checking with the other first?” Settle on a real dollar figure before you move on.
- “If one of us died, where would we want this money to go?”
Then pick one setup to try for a set stretch, say six months, and put a date on your calendar to look at it again together.
Before anyone opens an account
Couples in the experiment’s joint group got one month to open their account, and the paperwork is the quick part. Every setup above works better when each of you already knows what the other holds and owes.
This week, each of you write down every account and debt in your own name, with its current balance, then swap lists.