Appellant assigns as error the denial of its motion for a directed verdict on defendants’ counterclaim, made at the close of defendants’ evidence and renewed at the close of all of the evidence. In support of this assignment of error appellant contends that as a matter of law the evidence established that the parties acted under a mutual mistake of fact, that there was never a “meeting of the minds” and therefore no binding contract as to what stock was owned by plaintiff and what stock plaintiff authorized defendants to sell, and that any loss sustained by defendants was brought about by their own negligence. We do not agree.
[1, 2] In examining the language and actions of the parties in order to determine if a binding contract resulted, the test to be applied is objective and not subjective. 13 Williston on Contracts, 3rd Ed., § 1536. “The rule supported by the authorities is that if, in the expression of the intention of one of the parties to an alleged contract, there is error, and that error is unknown to, and unsuspected by, the other party, that which was so expressed by the one party and agreed to by the other is a valid and binding contract, which the party not in error may enforce. In other words, a party to a contract cannot avoid it on the ground that he made a mistake where there has been no misrepresentation, there is no ambiguity in the terms of the contract, and the other contractor has no notice of such mistake and acts in perfect good faith.” 17 Am. Jur. 2d, Contracts, § 146, p. 492.
[3] When Morris Speizman, acting on behalf of plaintiff as its chief executive officer, phoned LeRoy Gross, defendants’ representative, and asked him to check the current market value of American Israeli Paper Mills stock which Mr. Speizman informed Mr. Gross that his company owned, he expressly identified the stock concerning which he inquired as the stock listed in the Charlotte Observer under quotations of the American Stock Exchange and selling at seven dollars1 per share. When Gross checked and confirmed the price, Speizman testified that: “I did at that time tell Mr. Gross that I owned over 18,000 shares of that stock. I did tell Mr. Gross at that time to sell 14,000 shares of that stock for the account of Morris Speizman Company, Inc.” Thus, objectively there was no mistake as to the identity of the stock which Speizman authorized defend*303ants to sell for the account of plaintiff company. The only mistake was the unilateral subjective mistake on the part of Speizman in believing that the stock which his company owned was the same stock which he had seen listed in the newspaper. Speizman undoubtedly acted in perfect good faith, but the mistake was his nevertheless. Once defendants accepted and acted upon his instructions, a binding contract resulted and plaintiff became estopped to deny liability. “In the final analysis, the objective theory of contracts, as distinguished from the subjective theory, is based on analogy to estoppel.” 1 Williston on Contracts, 3rd Ed., § 98, p. 362.
Nor do we find in this record any evidence that defendants had reason to know of Speizman’s mistake or that they were negligent in failing to question him as to whether the shares which he stated his company owned were American Israeli Paper Mills, Ltd., American shares, as listed and traded on the American Stock Exchange, or the underlying American Israeli Paper Mills, Ltd., Ordinary B shares. Defendants had not participated in any way when Speizman had originally acquired the shares for his company, and all that they knew concerning the shares was what Speizman told Gross in their brief telephone conversation. Nothing in that conversation would put defendants on notice that Speizman was acting under a mistaken impression in believing that the shares which his company owned were the same as the shares reported in the newspaper as listed on the American Stock Exchange to which he made specific reference. While he expressed surprise and delight that the shares which his company owned had apparently so substantially increased in Value, he did not inform Gross as to the amount of the increase, or exactly when the shares had been acquired, or what the original cost of the shares had been. During the telephone conversation, Gross consulted a Standard & Poor’s Stock Guide which was on his desk, and this revealed that the American Israeli Paper Mills, American shares, as traded on the American Stock Exchange, had ranged in price during 1967 from a low of 2 to a high of 5% and during 1968 from a low of 3% to a high of 7%. Therefore, there was nothing surprising in the fact that an investor in such shares might have realized a substantial gain. While the same Standard & Poor’s Stock Guide showed in a footnote “Amer shrs equals 8 ord par Is £ 1,” the existence of this footnote would not, in our opinion, put Gross on notice that his customer, Speizman, was *304operating under any mistake as to the nature of the shares which his company owned. From previous dealings between them, Gross knew Speizman to be an experienced and knowledgeable investor in many types of securities, and nothing occurred during the course of the telephone conversation which would reasonably put Gross on notice that his customer may not have been equally knowledgeable in this instance as to the nature of the securities which his company owned.
Appellant also assigns as error the trial court’s refusal to submit to the jury plaintiff’s tendered issues of mutual mistake and negligence and its failure to give the jury plaintiff’s tendered instructions on these issues. In these actions of the trial court we find no error. To justify the submission of an issue it must not only arise on the pleadings, but must be supported by competent evidence. Gunter v. Winders, 256 N.C. 263, 123 S.E. 2d 475. As noted above, these issues did not arise on the evidence in this case.
[4] Appellant contends the trial court erred in finding defendants’ witness Abernethy to be an expert in the field of buying and selling stocks and in permitting the witness to express an opinion in response to a hypothetical question. “Whether a witness has the requisite skill to qualify him as an expert is chiefly a question of fact, the determination of which is within the exclusive province of the trial judge.” To qualify a witness as an expert, “[i]t is enough that, through study or experience, or both, he has acquired such skill that he is better qualified than the jury to form an opinion on the particular subject. A finding by the trial judge that the witness possesses the requisite skill will not be reviewed on appeal unless there is no evidence to support it.” Stansbury, N. C. Evidence, 2d Ed., § 133, p. 316. Here, there was evidence that the witness had been engaged in the securities business in various capacities for many years, for more than twenty-five years as an official of a broker dealer firm. There was ample evidence to support the court’s finding that he was an expert in this field.
[5] Appellant contends the trial court erred, nevertheless, in stating its finding that the witness was an expert in the presence of the jury, citing Galloway v. Lawrence, 266 N.C. 245, 145 S.E. 2d 861. In that case the defendant, a surgeon in a malpractice suit, was offered as an expert witness. The trial court, in the presence of the jury, found him to be a medical expert. *305On appeal, the Supreme Court held that the ruling should have been made in the absence of the jury, “for it was an expression of opinion by the court with reference to the professional qualifications of the defendant” and “might well have affected the jury in reaching its decision that the child was not injured by the negligence of the defendant.” Accordingly, the Supreme Court held that the trial court’s comments made in the presence of the jury finding defendant to be a medical expert constituted prejudicial error, since “they dealt with the very questions which the jury was called upon to decide.” In the present case the witness involved was not a party to the litigation and finding him to be an expert in no way dealt with any question which the jury was called upon to decide. Under the circumstances of this case we find no prejudicial error when the trial court stated its ruling in the presence of the jury.
[6] We have considered appellant’s remaining assignments of error and find them without merit. Evidence as to prior transactions between Speizman and Gross, while not bearing directly upon the issues in the case, was relevant to establish the course of conduct customarily followed in transactions between the two men. This in turn could provide a basis for determining whether customary procedures were followed in the present case and whether these resulted in a binding contract between the parties. To be relevant, “it is not required that the evidence bear directly on the question in issue, and it is competent and relevant if it is one of the circumstances surrounding the parties, and necessary to be known to properly understand their conduct or motives, or to weigh the reasonableness of their contentions.” Bank v. Stack, 179 N.C. 514, 103 S.E. 6.
The court’s charge to the jury adequately declared and explained the law arising on the evidence given in the case and, considered as a whole and contextually, was free from prejudicial error. In the trial and judgment appealed from we find
No error.
Judges Britt and Morris concur.