Advomi Logo
Close this search box.

Mutual Wills Explained

This article aims to give an overview of mutual wills, including who they are most suitable for and a discussion on its pros and cons. Case law from different jurisdictions, including Singapore, the United Kingdom and Canada, will be reviewed for the reader’s easy reference.

The article will ultimately attempt to aid potential testators make an informed decision on whether mutual wills can be a viable option as their choice of testamentary instrument.

Definition of Mutual Wills

Mutual wills are identical wills made by two parties, usually spouses, to protect their estate and their children in the event that either or both the parties pass away. This is an alternative to both spouses making individual wills, which can be revoked at any time after the demise of one party. The crux of a mutual will lies in its irrevocability, and they are generally most suitable for couples who are certain of their wishes on both of their demise.

However, it is imperative for potential testators of a mutual will to note that this should not bar parties’ from dealing with their estate in the future. Should the mutual will be drafted as a contract, with clear and express provisions for dealing with the estate on one party’s demise, it should be enforceable. Further, even if there was no provision, the property can also be dealt with if the spirit of the will was adhered to.

Validity of Mutual Wills

The main concern for parties affirming mutual wills would undoubtedly be that of the survivor reneging on their promise. Should parties not alter their wills, there would practically be no difference had they made individual or mutual wills. However, it is precisely the fickle nature of the human heart that entices couples to draft mutual wills, which is an effective instrument for couples looking to restrict their partners’ actions on their demise.

The validity of mutual wills has garnered limited judicial interpretation in Singapore. However, cases from other jurisdictions have discussed this issue extensively and provided clarity and guidance into the nature of this instrument. This article would attempt to provide a brief summary and analysis of the relevant case law in Singapore and other jurisdictions.

The Singapore Position on Mutual Wills

Cases challenging the validity of mutual wills are few and far between. However, it is instructive to look at other cases dealing with the deceased’s testamentary intentions and apply the same to potential disputes involving mutual wills.

In Lai Min Tet and another v Lai Min Kin and another and another application [2004] 1 SLR(R) 499; [2004] SGHC 3, the deceased father’s interest in the property in question was legally transferred to one of his sons by virtue of the doctrine of survivorship. However, the Court found a resulting trust arose in favour of the father from whoever held the property at the material time. His letters to his sons repeatedly stated that whichever son held the property did so on behalf of the other sons, and therefore constituted written evidence of a trust. The father also executed a draft deed of severance to sever his joint tenancy. The Court found that the evidence in total showed the father’s unwavering intention that his four sons should inherit his estate equally.

In Tsu Soo Sin nee Oei Karen v Ng Yee Hoon [2008] SGHC 30, the Court held that the beneficiaries’ promise to make a gift to a third party would constitute a sufficient detriment and where the parties make mutual promises to make such a gift, each promise may be consideration for the other. Here, three sons of the deceased each promised they would give their sisters $2 million from their inheritance and it constituted consideration for the other’s promise. Hence, the agreement between them was an enforceable agreement. This can be distinguished from Lai Min Tet as the deceased’s intention was actually not adhered to in this case, as he had no intention to provide for any of his daughters.

The English Position

The English Courts proffered their interpretation of mutual wills In re Dale, Decd. Proctor V. Dale [1992 P. No. 154] in that case, a husband and wife each executed identical wills. Each will contained a bequest of all real and personal property in favour of the testators’ daughter and son, the plaintiff and defendant respectively, in equal shares or the survivor of them and appointed them executors. Two months later the husband died without having altered or revoked his will. Thereafter, the wife made a fresh will which revoked all former wills and testamentary dispositions and appointed the defendant as executor. She bequeathed to the plaintiff the sum of £300 and to the defendant the remainder of her property, valued at about £19,000.

The Court held that it is to be assumed that the first testator and the second testator had agreed to make and not to revoke the mutual wills in question. The performance of that promise by the execution of the will by the first testator is sufficient consideration by itself. It was also held that mutual benefit is also not necessary for the purpose of the requisite contract.

In Olins v. Walters [2009] 2 W.L.R. 1 (C.A. (Civ. Div.)) it was held that the intentions of Mr Walters and the deceased were sufficiently expressed in the contract to lay the foundations for the equitable obligations that bind the conscience of Mr Walters, as the survivor, in relation to the deceased’s estate. This was all the Court required to make a finding that mutual wills existed. It had been accepted that, if there was a valid contract for mutual wills, the doctrine operated by imposing a constructive trust on the survivor, because the deceased had performed her promise to leave her estate to him. The trust is thus immediately binding on him in relation to the Deceased’s property left to him on basis of the contract. It is not postponed to take effect only after the death of Mr Walters when the property, or what may be left of it, comes into the hands of his personal representatives.

Canadian Case Law

In Brewster v Lenzi 2010 BCSC 1488, each party’s will stated that should the other die first, the survivor would transfer one half of the contents of the house effects, and the deceased’s one half interest in the matrimonial home to their respective beneficiaries, but not the other, for their own use absolutely. The court held that the evidence clearly established a common intention between the parties, and their mutual agreement as to the ultimate disposition of the property, that was meant to be irrevocable and binding upon each of them. The court concluded that the property was intended to be held in trust by the surviving joint tenant, and to be dealt with only in accordance with the terms of the agreement. Once Peter Lenzi died, the obligation became irrevocable when Mrs. Lenzi accepted the benefit of survivorship conferred by the joint tenancy arrangement.

In Powell v Glover (2008), 42 E.T.R. (3d) 298 (Alta. Q.B.), 2008 ABQB 532, Kent J. found that the absolute gift to Jessie in Mervin’s will permitted Jessie to dispose of assets during her lifetime with only one limitation, namely that she not dispose of assets with the intent to defeat the trust.

In Edell v Sitzer (2001) OR (3d) 198, Cullity J. held that as the authorities on mutual wills insist that there be a binding contract between the deceased and the survivor, he was of the view that it should not matter whether the wills are made pursuant to an agreement or whether there is an agreement not to revoke existing wills. As well, the nature and extent of the property to which the trust attaches and the rights of the survivor to consume or dispose of the property after the other’s death should depend upon the terms of the agreement as disclosed by the evidence.


The Singapore Court’s approach to mutual wills, or to wills in general, would seem to be a fact-finding exercise guided by equity. The Court endeavours to decipher the testator’s true intention, taking into account not just testamentary instruments, but also other evidence such as letters sent by the deceased while he was still alive (Lai Min Tet). However, should the intended beneficiaries agree to deal with the deceased’s estate in a way other than the deceased intended, the deceased’s intention would be disregarded, especially when other parties have relied on the said agreement to their detriment (Tsu Soo Sin nee Oei Karen). This finding, albeit equitable at face value, could introduce uncertainty into the law.

In contrast, the English Courts have construed mutual wills in different guises, such as a contract or a constructive trust. However, it is argued that the overarching principal is that the intention of the testators must be respected i.e. in Olins. This may be juxtaposed to Tsu Soo Sin nee Oei Karen, where the Court actually preferred the intentions of the beneficiaries to that of the testator.

Potential Pitfalls

When one party is deceased

The biggest fear for parties to a mutual will is that the surviving party could dissipate the pool of assets. Even if the survivor does not change their will there can still be problems if they squander the estate or transfer it to parties other than the mutually intended beneficiaries. In these circumstances, it is possible that when the survivor dies and the mutual will is adhered to, there could be nothing left to distribute.

Be that as it may, case law have suggested that safeguards can be imposed on mutual wills. It would seem that an express provision to allow the surviving party in a mutual will to dispose of or alter the subject matter of the will is tenable (Edell). In any case, should there be no express provision, a constructive trust arises once the first party passes away and leaves the estate to the survivor (Olins) and the beneficiaries would have an equitable interest over the assets. Further, even if there was no express provision, the survivor could only dispose of the assets as long as it is in accordance with the intention of the trust (Powell).

Therefore, should there be no express provision in the will for the disposition of the assets, case law suggests that the survivor should be able to deal with the property freely, as long as the original intention of the will is upheld.

When both parties are still alive

On the other hand, some testators may be concerned that executing a mutual will would restrict them should they wish to sell their property in the future. Further, in certain scenarios, parties may also wish for the survivor to be able to deal with the assets independently, such as to sell or rent the property to fund their medical fees. One way to circumvent this potential issue is to draft the will akin to a contract, which expressly sets out the rights of the surviving party. Essentially, the mutual will should be seemed as a contract between two parties rather than a traditional will.

For example, the mutual will could have a clause that deals with immovable properties, instead of specifying an address. Parties can then sell their property as whatever new property they purchase would still be covered under the existing mutual will. Even if there is a clause stating that the house cannot be sold, they could also jointly agree to revoke the will and deal with the property.

On the other hand, should their intention be that the survivor would be able to sell the property, there need to be a clear clause in the will evincing such an intention. It may also be helpful to expressly indicate where the proceeds from the sale should go to.


Drafting a mutual will can be a potentially precarious affair. Even if the will appears iron-clad, the parties have several avenues to venture beyond the expressly defined parameters.

Therefore, the safest, albeit constrictive, way of preserving the family’s assets and ensuring that they eventually go to the intended beneficiaries would be to execute a mutual will that expressly state that specific high-value assets, such as immovable property, cannot be disposed of on one party’s demise.

In the alternative, should the intention of the parties be for the survivor to deal with the property as he deems fit, restrictions can also be placed on the manner which the proceeds are utilised. The beneficiaries may also be advised to lodge a caveat over the property so that they will be informed of any transfer of the property.

More resources


Tokenisation of real world assets (RWAs)

Introduction Tokenisation of real world assets refers to breaking down high-value properties, whether tangible (such as art pieces) or intangible (such as financial instruments and…


Gambling Control Act

Introduction The Gambling Control Act 2022 (GCA) is a consolidation and update of previous gambling legislation including the Betting Act 1960, the Common Gaming Houses…



Introduction Retrenchment refers to the termination of an employee’s employment due to redundancy, restructuring or for cost saving reasons, as opposed to termination for poor…


Restraint of Trade Clauses in Employment Contracts

When drafting an employment contract, employers often include a restraint of trade clause in order to restrict what an ex-employee may do post-employment. As defined…


Understanding Crypto Fraud, Investigations and Asset Tracing part 3

After exploring the diverse landscape of blockchain and cryptocurrency frauds in our first article, and delving into the array of disputes in our second installment,…


Understanding Crypto Fraud, Investigations and Asset Tracing part 2

In continuation of our 3-part series unraveling the complexities of blockchain and cryptocurrency, our second installment will delve into the spectrum of Blockchain and Cryptocurrency…