Definition
A collateral power is a power over property granted to a person who holds no interest in that property. The holder of the power — called a mere stranger or collateral donee — derives no benefit from the estate itself; the power is given solely to enable a specific act, typically a conveyance, sale, or appointment, to be carried out. The classic example is a power of sale granted to an executor: the executor owns nothing in the estate, yet is authorized to sell its assets for the benefit of others.
The defining characteristic is the absence of any estate or beneficial interest in the power holder. This distinguishes collateral powers from powers that are appurtenant (held by someone with an interest in the land) or powers in gross (held by someone with some independent legal relation to the subject matter). A collateral power is a bare authority — nothing more.
Common Confusion
Collateral power is easily confused with two related but distinct concepts.
A power appurtenant (or power appendant) attaches to an estate the donee already holds. A tenant for life with authority to lease beyond the term of the life estate holds a power appurtenant — the power and the interest coexist in the same person. A collateral power holder has no such interest.
A power in gross resembles collateral power in that the holder may lack a possessory estate in the property, but in some treatments a power in gross attaches to a personal capacity or office the donee holds independently. Older authorities draw this line inconsistently. In historical sources, collateral power and power in gross are sometimes treated as synonyms; researchers should not assume uniformity across sources.
Why It Matters in Research
The term collateral power appears primarily in older equity and property materials — trust instruments, wills, conveyancing treatises, and early probate records. Its practical significance peaked in an era when formal distinctions among power types governed how a power was exercised, whether it survived the donee's death, and whether a defective execution could be aided in equity.
Several research traps arise:
First, the word "collateral" does not here mean secondary, subordinate, or pledged as security — all common legal uses of that word. Researchers encountering "collateral power" in a deed or trust instrument should not read it through the lens of secured lending or evidence doctrine.
Second, the taxonomy of powers (collateral, appurtenant, in gross) is a creature of classical common law property doctrine. Modern trust and property codes — including the Uniform Trust Code and Uniform Powers of Appointment Act — have largely displaced this vocabulary in contemporary drafting. A researcher working in post-2000 materials will rarely encounter the term; a researcher working in pre-1950 materials will need it.
Third, the practical stakes of classification were real. Whether equity would aid a defective execution of a power, whether the power survived the donee's death or incapacity, and whether the power could be released or suspended all turned in part on whether the power was collateral, appurtenant, or in gross. Understanding the classification is necessary to understand what the authorities are deciding.
Fourth, the executor-power-of-sale example embedded in Bouvier's definition is a durable illustration, but do not generalize it too broadly. Modern executor powers are now extensively regulated by statute, and the common law reasoning underlying the "collateral" characterization may have been superseded in a given jurisdiction.
Historical Dictionary Support
Bouvier's Law Dictionary defines collateral power as "a bare power given to a mere stranger, who has no interest in the estate or property to which the power relates; e.g. a power of sale given to executors," citing an early Kentucky authority. The definition is compact but accurate on the essential point: the holder's lack of any proprietary interest in the subject property is what makes the power collateral.
Bouvier's treatment is workmanlike rather than exhaustive. It correctly identifies the stranger-to-the-estate test and supplies the executor example. What it does not address is the doctrinal consequence of classification — particularly the equity-of-imperfect-execution doctrine, under which courts would, for powers appurtenant and in gross, sometimes complete a defective exercise to prevent injustice, but were historically more reluctant to do so for bare collateral powers. Researchers relying solely on Bouvier's definition will have the taxonomy but not the stakes.
Classical English equity treatises — particularly those on powers by Sanders and by Farwell — developed the three-part classification more fully and linked it to the consequences that flowed from each category. Those sources remain useful for understanding why the classification mattered, not merely what it was.
Jurisdictional Note
The three-way taxonomy of powers (collateral, appurtenant, in gross) was received into American common law from English equity but was never uniformly applied across states. Some jurisdictions never gave the classification operative weight in their reported decisions. Researchers should not assume that a state court in 1890 would have applied Bouvier's framework without first confirming that the jurisdiction actually recognized and used the distinction.
Encyclopedia Cross-Reference
No Law Mind Encyclopedia entry addresses powers of appointment or property powers directly. For related collateral-doctrine research: civpro_177 (Impeachment by Contradiction and Collateral Matters Doctrine) and torts_30 (Defenses to Negligence — Collateral Source Rule) each use "collateral" in wholly different legal senses and are not substantively connected to collateral power as a property concept.