







Using an experiment in which 3.1 million bank customers were encouraged to save, we explore the mechanisms behind co-holding liquid savings and credit card debt. Theoretically, we first show that the joint responses of spending, saving, and borrowing to the nudge differ for different economic models of co-holding. Using machine learning techniques, we then find that the most responsive individuals reduce spending and increase their savings by 4.9% (206 USD PPP per month) while their credit card debt remains unchanged. For them, the marginal responses to the nudge are consistent with our model of co-holding for the purpose of self- or partner control.
Does Saving Cause Borrowing? Implications for the Coholding Puzzle
ABSTRACT Using an experiment in which 3.1 million bank customers were encouraged to save, we explore the mechanisms behind coholding liquid savings and credit card debt. Theoretically, we show that the joint responses of spending, saving, and borrowing to the nudge differ across economic models of coholding. Using machine learning techniques, we find that the most responsive individuals reduce spending and increase savings by 4.9% (206 USD PPP per month) while their credit card debt remains unchanged. These individuals' marginal responses to the nudge are consistent with our model of coholding for the purpose of self‐ or partner‐control.

Co-holding behaviour: unlocking the puzzle
This article seeks to explain why households decide to simultaneously hold both credit and savings products. Beyond the arguments of ignorance or behavioural biases commonly used in the literature,...

The Co-holding Puzzle: New Evidence from Transaction-Level Data
Using detailed and highly disaggregated data on household finances, we examine the<br>tendency of consumers to “co-hold” savings and debt simultaneously. The di
Disclosing the costs of co-holding liquid assets and high-interest debt has limited impact on behavior
Abstract Why do consumers simultaneously maintain low-yield liquid assets and high-interest revolving debt? This behavior, known as ``co-holding,'' affects 23\% of credit card users in our sample from a major international bank and costs the typical co-holder hundreds of dollars annually in unnecessary interest charges. Our analysis of 38 months of detailed banking records reveals that co-holding is remarkably persistent, with typical co-holders maintaining this behavior for most months observed. Our analysis also reveals that co-holding is not a static financial position: co-holders regularly deposit and withdraw from asset accounts while simultaneously making new credit card purchases. To test whether co-holding could be addressed through information disclosure, we conducted a large-scale field experiment (n = 125,328), providing clear information about co-holding behavior and its costs. Customers received targeted messages through their bank's mobile app, where they could easily transfer money from assets to pay down debt. Despite sufficient power to detect economically small effects, we found no meaningful changes in debt repayment amount, though customers did respond in other ways---making more frequent repayments and paying above required minimums. These results challenge explanations based on limited attention or information gaps and suggest that simple information disclosure, even when carefully designed and delivered through trusted channels, may not effectively address costly financial behaviors.

The Co-Holding Puzzle: New Evidence from Transaction-Level Data
The tendency of consumers to hold low-yield liquid savings while simultaneously holding high-cost unsecured credit on revolving credit lines is a long standing
Keeping Cash and Revolving Debt: How Consumers' Preference for Spending on Debit versus Credit Influences their Decision to Co-Hold
This paper investigates "co-holding'"–whereby consumers simultaneously maintain low-yield liquid assets and high-interest revolving debt–through the l
Intra-Household Frictions, Anchoring, and the Credit Card Debt Puzzle
Abstract I study how intra-household frictions and anchoring contribute to the credit card debt puzzle, the co-holding of high-cost debt, and low-yield liquid assets. First, I find couples co-hold 42% more as units than as individuals relative to income. Moreover, in a natural experiment, couples do not cooperate to reduce high-cost debt, suggesting that intra-household frictions contribute to co-holding. Second, I find individuals who regularly make credit card debt payments equal to or near the minimum account for 59% of individual co-holding. The evidence suggests anchoring to the minimum payment contributes to co-holding via these low payments.

The Coholding Puzzle: New Evidence from Transaction-Level Data
Abstract Why do individuals pay debt interest when they could use their savings to pay down the debt? We explore why individuals “cohold” debt and savings using detailed and highly disaggregated daily-level data on household finances. We find that coholding mostly occurs in short spells within the month and the level of coholding is typically modest. Periods of coholding are not associated with shocks at the individual level. We show that mental accounting has a role to play in explaining coholding, in particular how individuals allocate different categories of expenditure to accounts in credit and debit.

Consumption Response to Credit Expansions: Evidence from Experimental Assignment of 45,307 Credit Lines
In a field experiment that constructs a randomized credit limit shock, participants borrow to spend 11 cents on the dollar in the first quarter and 28 cents by the third year. Effects extend to those far from the limit, those who had the new limits as available credit, and those with a liquid asset buffer. In the short-run, flexible and installment contracts are used in tandem, with unconstrained using installments more. Long-run borrowing is predominantly using installments. Near limits, participants borrow when credit expands but save out of constraints when limits are tight. Findings support a buffer-stock interpretation emphasizing precautionary saving.
Overconfidence and the Credit Card Debt Puzzle
This article investigates the credit card debt puzzle. Simultaneously holding credit card debt and liquid assets is puzzling given the sizeable difference between interest rates of debt and assets. However, this behavior is common—about 31% of households in the 2016 Survey of Consumer Finances. The cost of co-holding may be justified if consumers anticipate future restrictions in credit or if they need to maintain liquidity. Other existing explanations for co-holding include impulsive spending and low financial literacy. This research reveals a new explanation for the credit card debt puzzle: consumers’ overconfidence of their financial knowledge. Using a Coarsened Exact Matching method, we found that overconfident consumers were 20%–40% more likely to co-hold credit card debt and liquid assets.
Balancing Savings and Debt: Findings from an Online Experiment
Many consumers have savings and debt at the same time, and so are faced with a trade-off: how much debt to pay down versus how much savings to retain. This brie
Knowing When to Spend: Unintended Financial Consequences of Earmarking to Encourage Savings
Maintaining savings is an important financial goal. Yet there are times when savings should be spent, such as when people face unavoidable costs, and spending their savings allows them to avoid high interest rate debt. Existing behavioral research has focused on consumer decisions between savings and discretionary spending and has proposed interventions to promote savings in these contexts. However, when spending is not discretionary, such interventions could risk exacerbating a pattern found in economic research in which people borrow high interest rate debt while maintaining savings that earn low levels of interest. To examine how mental accounting interacts with considerations of personal responsibility and guilt to contribute to this pattern, this article explores whether people spend their savings when they need money most: during emergencies. Six studies reveal that people's tendency to preserve savings by borrowing from a high interest rate credit option varies as a function of the savings’ intended use. Paradoxically, people are most likely to turn to high interest rate credit with the belief that doing so is the responsible option.

The Credit Card Debt Puzzle and Noncognitive Ability
Abstract Many households concurrently hold low-yield liquid assets while incurring costly credit card debt. In our sample, more than 80% of households with credit card debt also have low-yield liquid assets. Using data from the Health and Retirement Study (N = 30,517), we examine the role of noncognitive skills as well as the economic, financial, and demographic factors that affect the likelihood of co-holding. We find that the “Big Five” personality traits have a statistically significant and economically important effect: households with a more agreeable, introvert, and less conscientious head of household are more likely to co-hold. We also examine the role of intra-household dynamics.

Payment Rewards and Credit Card Debt: Experimental Evidence
We report on a controlled laboratory experiment in which participants make consumption, saving, and credit card repayment decisions when credit card purchases e
The Credit Card Debt Puzzle: The Role of Preferences, Credit Access Risk, and Financial Literacy
Abstract. We use the 1979 National Longitudinal Survey of Youth to revisit what is termed the credit card debt puzzle: why consumers simultaneously co-hold high-interest credit card debt and low-interest assets that could be used to pay down this debt. Relative to individuals with no credit card debt but positive liquid assets, borrower-savers have very different perceptions of future credit access risk and use credit cards for precautionary motives. Moreover, changing perceptions about credit access risk are essential for predicting transitions among the two groups. Preferences and the composition of financial portfolios also play a role in these transitions.

Credit Card Debt Puzzles and Debt Revolvers for Self Control
Abstract Most US credit card holders revolve high-interest debt, often with substantial liquid and retirement assets. We model separation of accounting from shopping allowed by credit cards, in a rational, dynamic game. When the shopper is more impatient than the accountant, selling assets to repay debt is not necessarily optimal, as the shopper can restore debt. Modest relative impatience generates asset-debt co-existence and target utilization rates, matching incidence and median assets of debt revolvers with substantial assets. Empirical evidence is consistent with a role for spending control considerations, after allowing for standard determinants of credit card debt.
