DENECKE, Justice.

Plaintiff brought this action for equipment rentals against the defendant Dr. Bennett and two others. In addition to making a general denial, Dr. Bennett alleged as a defense that the rentals were to a de facto corporation, Aero-Fabb Corp., of which Dr. Bennett was an incorporator, director and shareholder. He also alleged plaintiff was estopped from denying the corporate character of the organization to whom plaintiff *66 rented the equipment. The trial court held for plaintiff. Dr. Bennett, only, appeals.

On January 22, 1970, Dr. Bennett signed articles of incorporation for Aero-Fabb Co. The original articles were not in accord with the statutes and, therefore, no certificate of incorporation was issued for the corporation until June 12, 1970, after new articles were filed. The leases were entered into and rentals earned during the period between January 22nd and June 12th.

Prior to 1953 Oregon had adopted the common-law doctrine that prohibited a collateral attack on the legality of a defectively organized corporation which had achieved the status of a de facto corporation. See, for example, Marsters v. Umpqua Oil Co., 49 Or. 374, 377, 90 P. 151, 12 LRA(ns) 825 (1907).

In 1953 the legislature adopted the Oregon Business Corporation Act. Oregon Laws 1953, ch. 549. The Model Business Corporation Act was used as a working model for the Oregon Act. 1952 Oregon State Bar Committee Reports, p. 5.

ORS 57.321 of the Oregon Business Corporation Act provides:

‘Upon the issuance of the certificate of incorporation, the corporate existence shall begin, and such certificate of incorporation shall be conclusive evidence that all conditions precedent required to be performed by the incorporators have been complied with and that the corporation has been incorporated under the Oregon Business Corporation Act, except as against this state in a proceeding to cancel or revoke the certificate of incorporation or for involuntary dissolution of the corporation.’

ORS 57.793 provides:

‘All persons who assume to act as a corporation without the authority of a certificate of incorporation issued by the Corporation Commissioner, shall be jointly and severally liable for all *68 debts and liabilities incurred or arising as a result thereof.’

We hold the principle of de facto corporation no longer exists in oregon.

The defendant also contends that the plaintiff is estopped to deny that it contracted with a corporation.

When a defendant seeks to escape liability to a corporation plaintiff by contending that the plaintiff is not a lawful corporate entity, courts readily apply the doctrine of corporation by estoppel. Thompson Optical Institute v. Thompson, supra (119 Or. 252, 237 P. 965), well illustrates the equity of the doctrine in this class of cases R. A. Thompson carried on an optical business for years. He then organized a corporation to buy his optical business and subscribed to most of the stock in this corporation. He chaired the first meeting at which the Board resolved to purchase the business from him. The corporation and Thompson entered*71 into a contract for the sale of the business which included a covenant by Thompson not to compete. Thereafter, Thompson sold all of his stock to another individual. Some years later Thompson re-entered the optical business in violation of the covenant not to compete. The corporation brought suit to restrain Thompson from competing. Thompson defended upon the ground that the corporation had not been legally organized. We held, ‘The defendant cannot be heard to challenge the validity of the contract or the proper organization of the corporation.'[FN2] 119 Or. at 260, 237 P. at 968. #p#分页标题#e#

On the other hand, when individuals such as the defendants in this case seek to escape liability by contending that the debtor is a corporation, Aero-Fabb Co., rather than the individual who purported to act as a corporation, the courts are more reluctant to estop the plaintiff from attacking the legality of the alleged debtor corporation. Ballantine, supra, at 96; 8 Fletcher, Cyclopedia of the Law of Private Corporations (perm.ed.) s 3914, p. 228.

The most appealing explanation of why the plaintiff may be estopped is based upon the intention of the parties. The creditor plaintiff contracted believing it could look for payment only to the corporate entity. The associates, whatever their relationship to the supposed corporate entity, believed their only potential liability was the loss of their investment in the supposed corporate entity and that they were not personally liable. *72 Cranson v. International Business Machine Corp., 234 Md. 477, 200 A.2d 33, 38-39 (1964); Namerdy v. Generalcar, 217 A.2d 109 (D.C. Ct. of App. 1966); E. Merrick Dodd, Jr., Partnership Liability of Stockholders in Defective Corporations, 40 Harv.L.Rev. 521, 552 (1927).

From the plaintiff-creditor's viewpoint, such reasoning is somewhat tenuous. The creditor did nothing to create the appearance that the debtor was a legal corporate entity. The creditor formed its intention to contract with a debtor corporate entity because someone associated with the debtor represented, expressly or impliedly, that the debtor was a legal corporate entity.

We need not decide whether the doctrine of corporation by estoppel would apply in such a case as this. The trial court found that if this doctrine was still available under the Business Corporation Act defendants did not prove all the lements necessary for its application, and, moreover, it would be inequitable to apply the doctrine.[FN3]

Under the explanation stated above for the application of the doctrine of estoppel in this kind of case, it is necessary that the plaintiff believe that it was contracting with a corporate entity. The evidence on this point is contradictory and the trial court apparently found against defendants.

The trial court found, and the evidence supported the finding, that two of the leases entered into by plaintiff were with ‘Kenneth L. Davenport, dba Aero-Fabb Co.’ The other was with ‘Kenneth L. Davenport, dba Aero-Fabb Corp.’ ‘Aero-Fabb Corp.’ was never the corporate name; the name of the corporation for which a certificate was finally issued was ‘Aero-Fabb Co.’ The correspondence and records of plaintiff sometimes referred to the debtor as ‘Aero-Fabb Co.’ and others as ‘Aero-Fabb Corp.’

Plaintiff's bookkeeper testified that she thought it was a corporation because, ‘This was the way the information was given to me.’ It is uncertain whether the information was given to her by someone employed by plaintiff or by a company with whom she made a credit check. In any event, plaintiff's salesman said Mr. Davenport, speaking for the organization, stated several times that he was in a partnership with Drs. Gorman and Bennett. The salesman was dubious and checked the title to the land on which the debtors' operation was being conducted and found it was in the name of the three defendants as individuals. #p#分页标题#e#

A final question remains: Can the plaintiff recover against Dr. Bennett individually?

In the first third of this century the liability of persons associated with defectively organized corporations was a controversial and well-documented legal issue. The orthodox view was that if an organization had not achieved de facto status and the plaintiff was not estopped to attack the validity of the corporate status of the corporation, all shareholders were liable as partners. This court, however, rejected the orthodox *74 rule. In Rutherford v. Hill, 22 Or. 218, 29 P. 546, 29 Am.St.R. 596, 17 L.R.A. 549 (1892), we held that a person could not be held liable as a partner merely because he signed the articles of incorporation though the corporation was so defectively formed as to fall short of de facto status. The court stated that under this rule a mere passive stockholder would not be held liable as a partner. We went on to observe, however, that if the party actively participated in the business he might be held liable as a partner.

We find the language ambiguous. Liability is imposed on ‘(a)ll persons who assume to act as a corporation.’ Such persons shall be liable ‘for all debts and liabilities incurred or arising as a result thereof.’

We conclude that the category of ‘persons who assume to act as a corporation’ does not include those whose only connection with the organization is as an investor. On the other hand, the restriction of liability *75 to those who personally incurred **1114 the obligation sued upon cannot be based upon logic or the realities of business practice. When several people carry on the activities of a defectively organized corporation, chance frequently will dictate which of the several active principals directly incurs a certain obligation or whether an employee, rather than an active principal, personally incurs the obligation.

We are of the opinion that the phrase, ‘persons who assume to act as a corporation’ should be interpreted to include those persons who have an investment in the organization and who actively participate in the policy and operational decisions of the organization. Liability should not necessarily be restricted to the person who personally incurred the obligation.

The trial court found that Dr. Bennett ‘acted in the business venture which was subsequently incorporation on June 12, 1970.’

The proposed business of the corporation which was to be formed was to sell airplanes, recondition airplanes and give flying lessons. Land was leased for this purpose. Equipment was rented from plaintiff to level and clear for access and for other construction.

There is evidence from which the trial court could have found that while Drs. Bennett and Gorman, another defendant, entrusted the details of management to Davenport, they endeavored to and did retain some control over his management. All checks required one of their signatures. Dr. Bennett frequently visited the site and observed the activity and the presence of the equipment rented by plaintiff. He met with the organization's employees to discuss the operation of the business. Shortly after the equipment was rented and before most of the rent had accrued, Dr. *76 Bennett was informed of the rentals and given an opinion that they were unnecessary and ill-advised. Drs. Bennett and Gorman thought they had Davenport and his management ‘under control.’

This evidence all supports the finding that Dr. Bennett was a person who assumed to act for the organization and the conclusion of the trial court that Dr. Bennett is personally liable.

Affirmed.