Notice — Actual and Constructive (Section 3)

The doctrine of notice is the equitable spine of the Transfer of Property Act, 1882. Section 3 — by its fifth definitional paragraph and three Explanations — fixes when a person is said to have notice of a fact and when, though he claims ignorance, the law treats him as if he knew. The provision is short, but its operation reaches every other equity in the Act: the rights of an unpaid seller under Section 55, the priority of a charge under Section 100, the protection of a purchaser from an ostensible owner under Section 41, the doctrine of part performance under Section 53A, and the priorities between successive mortgagees under Sections 78 and 79 all turn on whether the transferee had notice of the fact in question. Without the definition in Section 3, the equitable architecture of the Act would collapse.

Notice answers a single legal question: as between two innocent claimants to the same property, who must give way? Equity's answer is that the claimant who knew, or ought to have known, of the prior right is bound by it; the claimant who neither knew nor ought to have known takes free. The Section 3 definition supplies the test for that knowledge.

Statutory text — Section 3, paragraph 5

The fifth paragraph of Section 3 reads: "a person is said to have notice of a fact when he actually knows that fact, or when, but for wilful abstention from an inquiry or search which he ought to have made, or gross negligence, he would have known it."

The amending Act of 1929 rewrote this paragraph and added the three Explanations that follow it. The drafting strategy is one of categories: the main paragraph defines the general test (actual knowledge or imputed knowledge through wilful abstention or gross negligence); Explanation I deals with registration; Explanation II deals with possession; Explanation III deals with notice through an agent. Each Explanation creates a statutory presumption that, in equity's language, is irrebuttable — the person dealing with the property is fixed with notice, and is not allowed to plead that he in fact did not know.

Actual notice — express knowledge from the transaction

Actual notice (also called express notice) is notice whereby a person acquires actual knowledge of the fact. The classical statement, from Lloyd v Banks (1868) LR 3 Ch App 488, requires that the mind of the person to be charged "has in some way been brought to an intelligent apprehension of the nature of the encumbrance which has come upon the property, so that a reasonable man, or an ordinary man of business, would act upon the information and would regulate his conduct by it." Vague rumours and casual conversation are not enough; the information must be definite and given in the course of negotiations by a person interested in the property. Notice received in a previous transaction may have been forgotten and does not bind in a later, independent transaction.

What looks like rumour can, however, become a starting point for inquiry. If an intending purchaser is told that some person claims title, that mere assertion is not actual notice of the title; but it is sufficient to put him on inquiry, and what an ordinary inquiry would have disclosed is then imputed to him as constructive notice. The line between actual and constructive notice often shifts on this hinge.

Constructive notice — the equitable extension

Constructive notice is the equity which treats a man who ought to have known a fact as if he actually does know it. The classical exposition is by Vice-Chancellor Wigram in Jones v Smith (1841) 1 Hare 43, which sorted constructive notice into two classes: cases of actual knowledge of an encumbrance, where the law charges the purchaser with notice of every fact a reasonable inquiry would have revealed about that encumbrance; and cases of designed abstention from inquiry for the purpose of avoiding notice. The first class is the doctrine of inquiry; the second is the doctrine of wilful blindness.

Indian courts have added a third — gross negligence — by reading it into the words "wilful abstention from an inquiry or search which he ought to have made". The Privy Council in Imperial Bank of India v U Rai Gyaw Thu AIR 1923 PC 211 confirmed that omission to search the register kept under the Indian Registration Act, 1908 may itself amount to gross negligence and so attract the consequences of notice. The same principle has been extended to omission to inspect the Record of Rights, the Revenue Register and the title deeds the vendor is obliged to produce in a sale of immovable property under Sections 54 to 57.

The presumption raised by constructive notice is, in equity's language, irrebuttable. As Eyre CB said in Plumb v Fluitt (1791) 2 Anst 432, constructive notice is no more than evidence of notice, but the presumption is so violent that the court will not allow even of its being controverted. The doctrine, however, is available only to one who has acted innocently himself. A vendor who is bound to disclose an encumbrance cannot turn around and plead that the purchaser had constructive notice through the register.

Wilful abstention from inquiry

The first limb of the imputed-knowledge test is wilful abstention from an inquiry or search the person ought to have made. The Calcutta High Court, following Joshua v Alliance Bank (1895) ILR 22 Cal 185, has read "wilful abstention" to mean abstention that shows lack of bona fides. A person who refuses to accept a registered letter cannot afterwards plead ignorance of its contents. The principle that means of knowledge is equivalent to knowledge has been applied to a banker's passbook to fix a customer with knowledge and ratification of entries in it.

Where a purchaser is told that the title deeds are with a bank for safe custody and he omits to make inquiry of the bank, he is fixed with notice of the pledge if the deeds prove to be pledged. Where a charge is registered but the agent of a subsequent mortgagee omits to look into the Sub-Registrar's register, the mortgagee is taken to have constructive notice of the charge. The duty of inquiry is shaped by what a prudent purchaser of the same class of property would do in the ordinary course of business.

Gross negligence — the equitable test

Gross negligence is the second limb of the imputed-knowledge test. Mere want of caution is not penalised with constructive notice; what is required is negligence so gross that a court of equity will treat it as evidence of fraud, although morally the party charged may be perfectly innocent. The phrase, as Wigram VC explained in Jones v Smith, was invented by the courts of equity to extend their jurisdiction over cases that fell short of fraud but were equally unjust to leave uncorrected.

Romer J in Re City Equitable Fire Insurance Co [1925] Ch 407 explained the modern view that the real distinction between gross negligence and ordinary negligence lies not in the quality of the inattention but in the extent of the duty to take care that the situation imposes. Lord Selborne in Dixon v Muckleston (1872) 8 Ch App 155 referred gross negligence to the doctrine of estoppel: the man who has armed another with the apparent power of dealing with property is bound by the use the other makes of that apparent power.

The leading Indian authority on the gross-negligence test is Lloyds Bank Ltd v PE Guzdar & Co AIR 1930 Cal 22, often cited as Ahmadsahib v Magnesite Syndicate AIR 1916 Mad 1056 in the same line of cases. In Lloyds Bank the bank held title deeds of a Calcutta house by way of equitable mortgage. The mortgagor represented that he wished to sell to clear the overdraft and asked for the deeds back, claiming that a prospective purchaser would beat him down on price if the pledge were known. The bank, departing from its usual practice, returned the deeds; the mortgagor used them to obtain a fresh mortgage from another bank. The first bank's mortgage was postponed to the second bank's mortgage. The court held that returning the deeds in those circumstances was gross negligence enough to enable the fraud, and the priority shifted accordingly. The case is the textbook illustration of how gross negligence operates not as fraud, but as an estoppel against the negligent prior encumbrancer.

Explanation I — registration as constructive notice

Explanation I supersedes the conflict of pre-1929 case law on whether registration under the Indian Registration Act, 1908 is constructive notice of the contents of the registered instrument. The Bombay and Allahabad High Courts had held that registration is notice; the Madras High Court had held that it is not, on the ground that if the legislature had so intended it would have said so; the Calcutta High Court took an intermediate position that omission to search the register might or might not be gross negligence depending on the facts. The Privy Council in Tilakdhari Lal v Khedan Lal AIR 1921 PC 112, reviewing all the Indian decisions, held that the question was one of fact for each case, and approved Sir Lawrence Jenkins' decision in Manindra v Troylucko Nath (1899) 2 Cal WN 750.

Explanation I, inserted by the 1929 amendment, settled the dispute by enacting that any person acquiring immovable property is deemed to have notice of any registered instrument relating to that property as from the date of registration. The Explanation has its own conditions. The transaction must be one required by law to be effected by registered instrument; the registration must be in the manner prescribed by the Registration Act; the property must be in the same sub-district as the place of registration, or, where the property lies in several sub-districts or where registration was effected under Section 30(2) of the Registration Act in another district, registration operates as notice from the date when a memorandum is filed in the sub-district where the property lies. The two provisos to Explanation I make these conditions explicit.

The Supreme Court in Suraj Lamp & Industries v State of Haryana (2012) 1 SCC 656, and the line of decisions following Tilakdhari Lal, confirm the operation of the Explanation: a registered deed is constructive notice and a deemed notice under Section 3 TPA. A plea of bona fide purchaser without notice cannot be sustained against a registered instrument duly entered in the register and properly indexed. Any person dealing with immovable property is deemed to have knowledge of all duly registered instruments relating to that property. The objective of registration — to provide a public record on which every dealer with property can rely — is served by treating registration as the legal equivalent of inquiry and discovery.

Three corollaries follow. First, the registration of a puisne mortgage is not notice to a prior mortgagee under Section 58, because Explanation I notifies subsequent transferees; a prior mortgagee has no occasion to search for transactions that postdate his own. Second, an unregistered document is unenforceable to transfer immovable property and registration of an instrument that is not compulsorily registrable does not amount to constructive notice. Third, the registration must be in the proper book and properly indexed; misplaced entries in Book No 4 instead of Book No 1 do not operate as notice, by force of the second proviso to Explanation I.

Explanation II — possession as constructive notice

Explanation II enacts that any person acquiring immovable property is deemed to have notice of the title of any person who is for the time being in actual possession of the property. The provision codifies the equitable rule of Daniels v Davison (1809) 16 Ves 249 and Barnhart v Greenshields (1853) 9 Moo PC 18, which the English courts had long applied: possession by a third person is a fact that puts the world on inquiry as to the title under which that person holds.

The Supreme Court in R K Mohammed Ubaidullah v Hajee C Abdul Wahab (2000) 6 SCC 402 reformulated the rule for Indian conditions. With reference to subsequent purchasers, it is essential to make inquiry as to the title or interest of the person in actual possession as on the date of the sale transaction. Actual possession is itself constructive notice of the title, if any, of the person in possession. A subsequent purchaser must inquire as to the further interest, the nature of possession and the title under which the person continues in possession on the date of the purchase.

The English foundation case Hunt v Luck [1902] 1 Ch 428 supplies the limit. The possession that operates as notice must be actual and exclusive, not constructive or formal. A purchaser who finds his vendor in possession is not affected with notice that the vendor is in possession as a tenant of a third party, because the appearance of the vendor in possession is consistent with full ownership. The rule operates only when the visible state of the property is inconsistent with the vendor's full proprietary right and so puts the purchaser on inquiry. Where the visible facts are consistent with the title that the vendor claims, the purchaser is not bound to inquire further.

The doctrine has been extended in two important directions. First, the possession of a tenant under a lease of immovable property is notice not only of the terms of the tenancy but of any collateral right the tenant may hold against the vendor, including a right of pre-emption, a right of renewal, or a right under an unregistered agreement of sale. Second, the possession of a person claiming under Section 53A part performance is constructive notice of the part-performance defence: a purchaser from the vendor who fails to inquire of the person in possession is fixed with notice of his Section 53A right.

The limits are equally well settled. Constructive possession is not notice. Possession of a small fraction of a building does not put the purchaser on inquiry as to rights claimed in the whole. Where the open possession of a tenant is consistent with the lessor's title — for example, where the rent is being paid to the lessor — the purchaser is entitled to assume that the only equity is the tenant's tenancy, and is not put on inquiry as to collateral agreements that the tenant may assert against the lessor.

Explanation III — notice through an agent (imputed notice)

Explanation III enacts that a person is deemed to have notice of any fact if his agent acquires notice of the fact while acting on his behalf in the course of business to which the fact is material; with a proviso that fraudulent concealment by the agent prevents the imputation as against any person who was a party to the fraud. The rule is the equitable expression of the maxim qui facit per alium facit per se — he who acts through another acts in person.

The 1929 amendment widened the prior definition. The earlier text spoke of information "given or obtained by his agent", which suggested express notice; the present Explanation III imputes any fact of which the agent has notice, whether express or constructive. Lord Chelmsford in Espin v Pemberton (1859) 3 De G & J 547 first used the phrase "imputed notice" to mark this category off from constructive notice properly so called.

The five conditions of imputed notice

The Explanation reads with five embedded conditions, four implicit in the words "whilst acting on his behalf in the course of the business to which that fact is material" and the fifth in the proviso. (i) The notice must have been received during the agency. Knowledge acquired by an agent before the commencement of the agency, or after its termination, is not imputed. (ii) The notice must have been received in the agent's capacity as agent, not in his personal capacity. (iii) The notice must have been received in the course of the agency business; employment of a solicitor in one transaction does not make him an agent for receiving notice in a subsequent independent transaction. (iv) The fact must be material to the agency business; an agent has no duty to acquire or transmit knowledge irrelevant to his agency. (v) The fact must not have been fraudulently concealed by the agent from the principal.

The exception — fraudulent concealment

The proviso to Explanation III displaces imputation where the agent fraudulently conceals the fact. As Fry LJ explained in Cave v Cave (1880) 15 Ch D 639, the exception rests on two grounds: the act done by the agent in committing the fraud is not done in his character of agent but in the character of a party to an independent fraud against his principal; and the circumstances raise the inevitable conclusion that the notice has not been communicated. The Privy Council adopted the same reasoning in Texas Co Ltd v Bombay Banking Co AIR 1929 PC 215.

The exception, however, is itself qualified. As against any person who was a party to or otherwise cognizant of the fraud, the imputation continues to operate; the principal cannot use the agent's fraud to defeat the very person who induced or shared the fraud. And, even where the agent has acted fraudulently, the principal will be deemed to have notice of anything an honest solicitor employed in the place of the fraudulent solicitor would have discovered in the ordinary course of business — the rule in Kennedy v Green (1836) 3 My & K 699.

Notice and the cognate provisions of the Act

Section 3's definition of notice operates as a master concept across the Act. Several provisions expressly turn on it.

Under Section 39, a transferee from a person whose property is burdened with a right of maintenance takes subject to that right if he had notice of it; under Section 40, a buyer with notice of a prior contract for sale is bound by it. Under Section 41, a purchaser from an ostensible owner is protected only if he acted in good faith after taking reasonable care to ascertain the transferor's power; the duty of reasonable care is the duty defined by the Section 3 test. Under the proviso to Section 100, no charge is enforceable against a transferee for consideration without notice. Under Section 53, a fraudulent transfer is voidable at the instance of any defrauded creditor, but not against a transferee in good faith and for consideration — good faith being shaped by the Section 3 test of notice.

The doctrine has its sharpest application in the priority rules of Sections 78 and 79 of the Act, which displace the prior mortgagee's priority where his fraud, misrepresentation or gross neglect has induced a subsequent mortgagee to advance money. The same operates between successive mortgagees under Sections 67 to 77 by deposit of title deeds, where the gross-negligence rule of Lloyds Bank v Guzdar sets the standard. Read with the rules on marshalling and contribution, Section 3 supplies the doctrinal grammar of priorities.

Notice and Section 53A part performance

The interaction of notice with Section 53A deserves separate mention. Section 53A protects a transferee in possession under an unregistered written contract against the transferor and persons claiming under him. A purchaser from the transferor who, at the time of his purchase, finds the property in the actual possession of a stranger and fails to inquire of him is fixed with constructive notice of the stranger's right to claim the part-performance defence. The decision in Achaldas Durgaji Oswal v Ramvilas Gangabisan Heda (2003) 3 SCC 614 confirms that the possession of the transferee under Section 53A is a fact that, by Explanation II, puts every subsequent purchaser on inquiry; and the part-performance right is the very fact of which the inquiry would give notice.

Notice and the Section 41 ostensible owner defence

Section 41 protects a transferee from an ostensible owner only if the transferee took reasonable care to ascertain that the transferor had power to make the transfer and acted in good faith. The two limbs of the protection — reasonable care, and good faith — are policed by the Section 3 doctrine of notice. The transferee who omitted to search the register, who did not inspect the Record of Rights, who did not ask for the title deeds, or who took the deed on a story whose obvious gaps he did not pursue, fails the test of reasonable care and is fixed with constructive notice of the true owner's title. The defence is then unavailable. Section 41 and Section 3, in this respect, are two halves of one doctrine.

Notice in the proviso to Section 100 — charges

The proviso to Section 100 makes the doctrine of notice the gatekeeper between the charge-holder and the bona fide purchaser. A charge cannot be enforced against immovable property in the hands of a transferee for consideration who took without notice of the charge. The proviso has its own statutory exceptions for charges that bind the property regardless of notice — municipal property tax, revenue arrears, certain personal-law charges — but the residue is governed by the Section 3 test. Where the charge has been registered, Explanation I makes notice automatic; where the charge-holder is in possession, Explanation II makes notice automatic; where the charge would have been discovered by the inquiry an ordinary purchaser would make, the gross-negligence rule of the main paragraph fixes the purchaser with notice. A charge that survives all three filters is a charge of which the purchaser was, in the eyes of equity, ignorant — and the proviso protects him.

Burden of proof

The burden of proving notice is on the party who asserts it. Section 101 of the Indian Evidence Act, 1872 places the burden of proving any fact on the party who would fail if no evidence were given on either side. The Supreme Court in Salim D Agboatwala v Shamalji Oddhavji Thakkar AIR 2021 SC 5212 held that the question whether a person has notice under Section 3 TPA is a matter of fact to be established on evidence, and a plea of constructive notice raised to sustain a plea of limitation cannot be accepted at the stage of an application for rejection of the plaint. The Section 3 inquiry is fact-bound: the categories of constructive notice are illustrative, not exhaustive, and the court will not freeze the doctrine into a rigid rule.

Distinctions for the exam

Actual versus constructive notice

Actual notice is knowledge in fact; constructive notice is knowledge that the law imputes to a person who ought to have known. Actual notice must be definite and given in the same transaction; constructive notice rises from the visible state of the property, the public register, the conduct of the parties, or the gross negligence of the purchaser.

Constructive notice versus imputed notice

Constructive notice is knowledge imputed to the person himself; imputed notice (Explanation III) is knowledge of an agent imputed to the principal. The first is direct equitable presumption; the second is the agency rule of identity between principal and agent.

Notice versus knowledge

Knowledge is a state of fact; notice is a legal conclusion. A person may have knowledge without notice (where the information was given in casual conversation that does not amount to notice in equity) and may have notice without knowledge (where the registration of an instrument relating to property capable of transfer fixes him with deemed notice though he never read the document).

Wilful abstention versus gross negligence

Wilful abstention is the deliberate avoidance of an inquiry the person ought to have made, with the object of avoiding knowledge. Gross negligence is the failure of an ordinary person to make the inquiry a prudent person would have made — a failure so marked that equity treats it as evidence of fraud. The first looks at intention; the second looks at conduct.

Worked illustrations

Illustration 1 — registration as notice. A executes a registered mortgage of his land in favour of B. A then sells the land to C without disclosing the mortgage. C, who did not search the register, claims to be a bona fide purchaser without notice. By Explanation I, C is deemed to have notice of B's mortgage from the date of registration. C takes the land subject to the mortgage. The result follows from Tilakdhari Lal v Khedan Lal as codified in Explanation I.

Illustration 2 — possession as notice. A enters into an unregistered written contract of sale with B and puts B into possession of the land. A then sells the same land to C by registered sale deed. C did not visit the land and did not inquire of B. By Explanation II read with the doctrine of part performance, C is deemed to have notice of B's possession and of the part-performance defence; C's purchase is subject to B's right under Section 53A.

Illustration 3 — gross negligence. A bank holds the title deeds of A's house by way of equitable mortgage. A asks for the deeds back to facilitate sale; the bank, departing from its usual practice of giving the deeds only to a solicitor, hands them to A. A uses them to obtain a fresh equitable mortgage from another bank. The first bank's mortgage is postponed to the second. The first bank's gross negligence in returning the deeds is the equitable estoppel that the doctrine in Lloyds Bank v Guzdar visits with the consequences of notice.

Illustration 4 — agent's notice. A employs S, a solicitor, to investigate title for the purchase of a plot, the parties being competent to transfer under Section 7. In the course of his investigation S discovers a recital in an earlier conveyance of an unregistered easement of way in favour of a neighbour. S does not communicate the recital to A. A takes the conveyance without inquiring of the neighbour. Under Explanation III, S's knowledge is imputed to A; A takes the plot subject to the easement. If, however, S fraudulently concealed the recital from A in collusion with the vendor, the proviso to Explanation III protects A — but only against the vendor and any other person who was party to the fraud, not against the neighbour who was innocent of it.

Why Section 3's definition of notice matters

The doctrine of notice is the price of efficient conveyancing. A property regime that protected only those buyers who actually knew of every prior right would reward ignorance and punish diligent vendors. A regime that bound every buyer to every prior right, regardless of knowledge or means of knowledge, would freeze the market. Section 3, with its three Explanations, draws a workable line. The buyer is bound by what is on the public register, by what is visible from the property itself, by what an honest agent would discover in the agency, and by what the buyer would discover if he made the inquiries an ordinary purchaser would make. Beyond that line, the law releases him.

The aspirant's working method on a Section 3 problem should be: identify the fact of which notice is alleged; ask whether the fact appears on the register (Explanation I), is visible through possession (Explanation II), or was known to an agent (Explanation III); if none of the three, ask whether the fact would have been discovered by the ordinary inquiry of a prudent purchaser; and only if all four routes fail, hold the purchaser to be without notice. Read alongside the rules on operation of transfer under Sections 8 to 11 and the protections for competent transferors, the doctrine of notice supplies the third leg on which the equitable architecture of the Act stands.

Frequently asked questions

What is the difference between actual notice and constructive notice under Section 3 TPA?

Actual notice (or express notice) is notice whereby a person acquires actual knowledge of a fact — the information must be definite, given in the course of negotiations by a person interested in the property, and brought to the mind of the recipient as a real apprehension of the encumbrance. Constructive notice is the equity which treats a person as if he knew a fact when, but for wilful abstention from an inquiry or search he ought to have made, or gross negligence, he would have known it. The first is a question of fact; the second is a presumption of law that, once raised, the courts will not allow to be rebutted.

Is registration of a deed under the Indian Registration Act constructive notice of its contents?

Yes, by force of Explanation I to Section 3 TPA, inserted by the 1929 amendment. The Privy Council in Tilakdhari Lal v Khedan Lal AIR 1921 PC 112 had earlier held that registration was at best a fact going to gross negligence; Explanation I now enacts that any person acquiring immovable property is deemed to have notice of any registered instrument relating to it from the date of registration, provided the registration is in the proper sub-district and the instrument is properly entered and indexed. The Supreme Court has confirmed that a registered deed is constructive notice and a deemed notice; a plea of bona fide purchaser without notice cannot be sustained against it.

Does possession of property by a third person give constructive notice of his title to a subsequent purchaser?

Yes. Explanation II to Section 3 TPA enacts that a person acquiring immovable property is deemed to have notice of the title of any person who is for the time being in actual possession. The Supreme Court in R K Mohammed Ubaidullah v Hajee C Abdul Wahab (2000) 6 SCC 402 held that a subsequent purchaser must inquire as to the title or interest of the person in actual possession on the date of the sale. The possession must be actual and exclusive — Hunt v Luck [1902] 1 Ch 428 confirms that constructive or formal possession does not suffice. The rule extends to the possession of a person claiming under Section 53A part performance.

When is the knowledge of an agent imputed to the principal?

Under Explanation III to Section 3 TPA, a person is deemed to have notice of a fact if his agent acquires notice while acting on his behalf in the course of business to which the fact is material. Five conditions must concur: (i) the notice must be received during the agency; (ii) by the agent in his capacity as agent; (iii) in the course of the agency business; (iv) on a matter material to the business; and (v) it must not have been fraudulently concealed by the agent. The proviso withdraws imputation where the agent has fraudulently concealed the fact, except as against any person who was a party to or cognizant of the fraud.

What is the gross-negligence test for constructive notice and what is the leading Indian case?

Mere want of caution is not penalised with constructive notice; what is required is negligence so gross that a court of equity treats it as evidence of fraud, although morally the party charged may be perfectly innocent (Wigram VC in Jones v Smith). The leading Indian application is Lloyds Bank Ltd v PE Guzdar & Co AIR 1930 Cal 22, where a bank holding title deeds by way of equitable mortgage returned them to the mortgagor in the belief that he wished to sell; the mortgagor used them to take a fresh mortgage, and the first bank's mortgage was postponed. Returning the deeds in those circumstances was gross negligence enough to enable the fraud and shift the priority. The Privy Council in Imperial Bank of India v U Rai Gyaw Thu AIR 1923 PC 211 had earlier held that omission to search the registration register may itself amount to gross negligence.

Is the burden of proving notice on the person who asserts notice or on the person who denies it?

The burden is on the person asserting notice. Section 101 of the Indian Evidence Act, 1872 places the burden of proving any fact on the party who would fail if no evidence were given on either side. The Supreme Court in Salim D Agboatwala v Shamalji Oddhavji Thakkar AIR 2021 SC 5212 held that the question whether a person has notice under Section 3 TPA is a question of fact to be established on evidence, and that a plea of constructive notice raised to sustain a plea of limitation cannot be decided at the stage of an application for rejection of the plaint. The categories of constructive notice are illustrative, not exhaustive, and the court will not freeze the doctrine into a rigid rule.