T.C. Memo. 2026-83: David T. Tunkl v. Commissioner of Internal Revenue

The $16.5 Million Mistake: Art Dealer’s Tax Bill Soars After Failed Picasso Deal

The stakes could not have been higher for David T. Tunkl, a high-flying art dealer whose tax troubles now serve as a cautionary tale for S corporation shareholders and art dealers alike. In a sweeping ruling that underscores the Tax Court’s willingness to wield its authority over complex financial transactions, Judge Landy of the United States Tax Court delivered a $5,142,307 deficiency against Tunkl for tax year 2018. The core dispute—whether $16.5 million received by Tunkl’s S corporation, Ganymede International, Inc., constituted a nontaxable loan, a refundable deposit, or taxable income—was resolved definitively in favor of the IRS. The court held that the funds were "received and failed to be reported as income," leaving Tunkl liable for the full tax deficiency plus penalties. The case serves as a stark reminder that the Tax Court will not hesitate to pierce the veil of corporate formalities when funds are used for personal benefit or lack the hallmarks of a legitimate loan or deposit. For art dealers and S corporation shareholders, the ruling signals that the IRS—and the Tax Court—are sharpening their focus on transactions that blur the line between financing and income.

The Art of the Deal: How a Picasso Painting Led to a Tax Disaster

The Picasso painting Man with Ice Cream Cone was supposed to be a golden ticket for David Tunkl—a $18.5 million purchase that would be flipped for $30.5 million to a Swiss buyer, netting him and his business partner, Robert Mnuchin, a tidy profit. But the deal never closed. The Picasso’s owner backed out, leaving Tunkl with $16.5 million wired into his S corporation’s bank account—funds he had already committed to another art purchase. When the Bacon painting deal fell through, Tunkl found himself in a financial freefall, forced to sign a $44 million demand note to Mnuchin. The Tax Court’s upcoming ruling would expose the fatal flaw in Tunkl’s informal approach: the $16.5 million was never a loan, a deposit, or anything but taxable income.

The disaster began with Tunkl’s long-standing role as an art dealer. After graduating from UCLA in 1977, he built a career brokering high-value art transactions, operating under the name David Tunkl Fine Art. By 2014, he had formalized his business as Ganymede, an S corporation of which he was the sole shareholder. But despite the corporate structure, Tunkl kept his operations informal. Ganymede had no dedicated bank account; all funds flowed through its JPMorgan Chase account, which Tunkl used for both business and personal expenses. The lack of separation between corporate and personal finances would later become a critical issue.

Tunkl’s relationship with Robert Mnuchin, a former Goldman Sachs banker who had opened the prestigious Mnuchin Gallery in New York, was equally informal. The two had collaborated on 13 transactions totaling between $100 and $200 million, with no written agreements in sight. Industry practice, Tunkl testified, favored handshake deals over contracts. This pattern of informality would define the Picasso transaction.

In late 2017, Tunkl identified the Picasso painting as a prime opportunity. He believed he could purchase it for $18.5 million and resell it to a Swiss buyer for $30.5 million. But Tunkl lacked the full purchase price. He approached Mnuchin to invest $16.5 million, framing the deal as a joint venture. The parties agreed to split profits—25% to Tunkl and 75% to Mnuchin on the first $30 million, with equal shares on any additional gains. Crucially, they never memorialized the terms in writing. Tunkl would finance the remaining $2 million himself.

On January 11, 2018, the Mnuchin Gallery wired $16.5 million to Ganymede’s JPMorgan Chase account. Mnuchin imposed no restrictions on how Tunkl used the funds. Tunkl, however, had other plans. At the same time he was negotiating the Picasso deal, he was also pursuing the purchase of Francis Bacon’s Figure Turning, a $21.85 million painting. Ganymede had signed an agreement to buy the Bacon painting in two installments: $4.4 million due on August 14, 2017, and $17.45 million due on January 10, 2018. Failure to pay the second installment would trigger termination and forfeiture of the $4.4 million deposit.

With no restrictions on the $16.5 million, Ganymede used the funds to cover the Bacon painting’s second installment, wiring $17.4 million to a Swiss bank account on January 16, 2018. Tunkl believed he could repay Mnuchin if the Picasso deal failed, thanks to the commissions he expected from both the Bacon painting and another contemporary art deal he was pursuing. That deal, however, collapsed, leaving Tunkl with no fallback revenue.

The Picasso deal unraveled in April 2018 when the owner withdrew from the sale. Tunkl, realizing he could not repay Mnuchin, flew to New York in June to confess the failure in person. Mnuchin’s legal team presented him with a $44 million demand note, backed by an agreement that required Tunkl to offer the Gallery first right of refusal on any future art opportunities. The note carried no repayment schedule, interest, or maturity date—just a promise to pay "on demand." Tunkl signed it under duress, later admitting he felt he had "no position to fight" Mnuchin.

The transaction’s informal nature—oral agreements, no written contracts, and unrestricted use of funds—would prove its undoing. The IRS would later argue that the $16.5 million was not a loan, a deposit, or an investment, but income. And the Tax Court would have to decide whether Tunkl’s control over the funds, combined with his inability to repay, transformed the transaction into taxable income.

Deposit, Loan, or Income? The Battle Over $16.5 Million

The stakes could not have been higher. The IRS asserted a deficiency of $16.5 million against Mr. Tunkl, arguing that the funds he received in January 2018 were not a deposit, not a loan, but taxable income under § 61(a)—the broadest definition of gross income in the Internal Revenue Code. Section 61(a) defines gross income as "all income from whatever source derived," including but not limited to compensation, business income, gains from property dealings, interest, rents, royalties, and dividends. The Supreme Court has repeatedly affirmed that this definition is all-encompassing, capturing any accession to wealth over which the taxpayer exercises dominion and control. Commissioner v. Glenshaw Glass Co., 348 U.S. 426 (1955). The IRS’s position hinged on two core arguments: first, that the $16.5 million was income because Tunkl had unrestricted access to the funds, and second, that his inability to repay the funds demonstrated that they were not a true loan but rather a constructive receipt of taxable income.

Mr. Tunkl, however, advanced a diametrically opposed position. He contended that the $16.5 million was a nontaxable customer deposit, arguing that the funds were held in trust for a future transaction and were subject to a legal obligation of repayment. Under this theory, the deposit would not constitute income because it was refundable and not yet earned. Alternatively, Tunkl argued that the funds constituted a nontaxable loan, asserting that the transaction was structured as a borrowing arrangement with a clear intent to repay, even if the repayment terms were informal. He pointed to the lack of written restrictions on the use of the funds as evidence that the transaction was not an income-producing event but rather a financing mechanism.

The IRS countered that Tunkl’s arguments failed on both counts. First, it argued that the funds were not a customer deposit because there was no written agreement or legal obligation to refund the money. The IRS relied on Commissioner v. Indianapolis Power & Light Co., 493 U.S. 203 (1990), which held that customer deposits are not income only if they are refundable with interest and the taxpayer has a legal obligation to repay. The IRS contended that Tunkl could not establish either condition, as the transaction was informal and lacked any documentation evidencing a deposit arrangement. Second, the IRS argued that the funds were not a loan because there was no enforceable obligation to repay. The IRS cited Welch v. Commissioner, 204 F.3d 1228 (9th Cir. 2000), which held that advances lacking a written agreement, fixed repayment schedule, or interest are not loans but rather taxable income. The IRS emphasized that Tunkl’s inability to repay the funds further undermined his loan characterization, as a true loan requires a reasonable expectation of repayment.

The dispute thus boiled down to a fundamental question: Did Mr. Tunkl have dominion and control over the $16.5 million in a manner that transformed it into taxable income? The IRS’s position rested on the dominion and control doctrine, a cornerstone of income taxation. Under this doctrine, as articulated in Rutkin v. United States, 343 U.S. 130 (1952), and James v. United States, 366 U.S. 213 (1961), a taxpayer has dominion and control over funds when they are free to use the money at will and derive readily realizable economic value from it. The IRS argued that Tunkl’s unrestricted use of the funds—including his inability to purchase a Bacon painting without them—demonstrated that he had complete dominion over the money, regardless of whether the funds were intended as a deposit or a loan. The IRS further contended that Tunkl’s failure to repay the funds was irrelevant to the income determination, as the taxability of funds under § 61(a) does not depend on the taxpayer’s ability to repay but rather on whether the funds were received and controlled.

For his part, Tunkl’s arguments hinged on the formalities of the transaction. He maintained that the lack of written documentation did not preclude the transaction from being a deposit or a loan, pointing to the oral agreement with Mr. Mnuchin as evidence of intent. Tunkl also emphasized that the funds were deposited into Ganymede’s bank account, suggesting that the money was held for a specific purpose—namely, the acquisition of a Picasso painting. However, the IRS dismissed these arguments, asserting that informal agreements and lack of documentation do not override the substance of the transaction. The IRS relied on Treas. Reg. § 1.61-1(a), which provides that income is taxable when received, regardless of the taxpayer’s intent or the transaction’s characterization. The IRS further argued that Tunkl’s inability to prove the existence of a legal obligation to repay or a refundable deposit shifted the burden to him to demonstrate that the funds were not income—a burden he failed to meet.

The battle lines were drawn. On one side, the IRS asserted that the $16.5 million was taxable income because Tunkl had dominion and control over the funds. On the other, Tunkl argued that the funds were either a nontaxable deposit or a nontaxable loan, despite the lack of formal documentation. The Tax Court would soon have to decide whether the substance of the transaction or the formalities of the agreement would prevail in determining the tax treatment of the $16.5 million.

Dominion and Control: Why the Court Ruled Against Mr. Tunkl

The Tax Court’s decision in Tunkl v. Commissioner, T.C. Memo. 2026-5 (Jan. 11, 2026), delivered a decisive blow to Mr. Tunkl’s argument that the $16.5 million wired by Mr. Mnuchin on January 11, 2018, was anything other than taxable income. The court’s reasoning hinged on the dominion and control doctrine, a bedrock principle under § 61(a) that has reshaped how the IRS and courts treat funds received by cash-method taxpayers. The opinion, written by Judge Albert G. Lauber, leaves no ambiguity: the $16.5 million was taxable income because Mr. Tunkl exercised unfettered control over the funds the moment they arrived in Ganymede’s account.

The Legal Framework: § 61(a) and the Dominion and Control Doctrine

The court began by grounding its analysis in § 61(a), which defines gross income as “all income from whatever source derived.” The Supreme Court has long held that this definition is broad and inclusive, capturing any accession to wealth over which the taxpayer has complete dominion and control. In Commissioner v. Glenshaw Glass Co., 348 U.S. 426 (1955), the Court clarified that income is realized when the taxpayer has “such control over it that, as a practical matter, he derives readily realizable economic value from it.” The Tax Court has repeatedly applied this principle to cash-method taxpayers, holding that funds received are taxable when the taxpayer is free to use them at will, regardless of whether they are later repaid or allocated to a specific purpose.

The dominion and control doctrine was further refined in Rutkin v. United States, 343 U.S. 130 (1952), where the Supreme Court ruled that even illegally obtained funds are taxable income if the taxpayer has unrestricted use of them. The Court’s logic was unassailable: “The power to dispose of income is the equivalent of ownership of it.” This principle was reaffirmed in James v. United States, 366 U.S. 213 (1961), which held that embezzled funds are taxable income because the embezzler has dominion and control over them. The Tax Court has since applied this doctrine to a wide range of transactions, from cryptocurrency staking rewards to shareholder advances, consistently ruling that unrestricted access to funds triggers income recognition.

The $16.5 Million Was Not a Nontaxable Customer Deposit

Mr. Tunkl’s first argument—that the $16.5 million was a nontaxable customer deposit—collapsed under the weight of the facts and the law. The court acknowledged that customer deposits are not income if they are refundable and the taxpayer has a legal obligation to repay them. This principle was established in Commissioner v. Indianapolis Power & Light Co., 493 U.S. 203 (1990), where the Supreme Court held that deposits held as security for future performance are not income because the taxpayer lacks unrestricted control over them. The Tax Court has since applied this rule to utility deposits, security deposits, and even cryptocurrency staking deposits, consistently ruling that refundable deposits are not taxable income.

However, the court found that Mr. Tunkl’s transaction with Mr. Mnuchin bore none of the hallmarks of a customer deposit. The relationship between the two men was not that of a customer and vendor, but rather that of joint investors in a Picasso painting deal. Mr. Tunkl testified that he and Mr. Mnuchin had successful dealings in the past, and the funds were wired as part of a profit-sharing arrangement where both parties expected to recoup their investment and split any excess profits. The court noted that Mr. Tunkl was not selling the Picasso painting to Mr. Mnuchin; instead, the two were co-investors in a venture to acquire and resell the painting for profit.

Crucially, the court found that Mr. Tunkl had no obligation to repay Mr. Mnuchin at the time the funds were wired. Mr. Tunkl’s testimony that he had a duty to repay from the start was deemed “unreliable, unsupported, and thoroughly unconvincing.” Instead, the documentary evidence—including a backdated invoice and an Agreement signed months later—demonstrated that the obligation to repay did not arise until June 14, 2018, when the deal fell through. The court emphasized that neither the invoice nor any email correspondence mentioned repayment, and Mr. Tunkl’s explanation that Mr. Mnuchin needed the backdated invoice for his financial accounting or tax records was unpersuasive. If there had been a duty to repay from the outset, the court reasoned, Mr. Mnuchin would have included that term in the agreement when the funds were wired.

The court’s final blow to Mr. Tunkl’s deposit argument was the fact that he was permitted to keep the entire $16.5 million. Mr. Tunkl repaid only $2.5 million of the $44 million debt, and the court found no evidence that this repayment was tied to the $16.5 million. The Addendum severed the $16.5 million from the larger debt, and the court noted that the Agreement permitted the Gallery to pursue a civil action if Mr. Tunkl failed to make payments—but no such action was ever commenced. The court concluded that Mr. Tunkl had failed to prove that the $16.5 million was a nontaxable deposit, stating:

“Mr. Tunkl has failed to demonstrate that he was not permitted to keep the entire $16.5 million.”

The $16.5 Million Was Not a Nontaxable Loan

Mr. Tunkl’s second argument—that the $16.5 million was a nontaxable loan—fared no better. The court applied the multifactor test from Welch v. Commissioner, 204 F.3d 1228 (9th Cir. 2000), which the Ninth Circuit (the court of appeals for this case) uses to determine whether a transaction qualifies as a true loan for federal tax purposes. The test considers seven factors:

1. Whether the promise to repay is evidenced by a note or other instrument;
2. Whether interest was charged;
3. Whether a fixed schedule for repayments was established;
4. Whether collateral was given to secure payment;
5. Whether repayments were made;
6. Whether the borrower had a reasonable prospect of repaying the loan and whether the lender had sufficient funds to advance the loan; and
7. Whether the parties conducted themselves as if the transaction were a loan.

The court found that none of these factors supported a finding of a true loan. First and foremost, there was no formal obligation to repay on January 11, 2018, the day the funds were wired. The obligation to repay did not arise until June 14, 2018, when Mr. Tunkl signed the Agreement. Neither the backdated invoice nor the Agreement contained any information about a repayment schedule, interest, or collateral. The Note, signed months later, was the first written documentation demonstrating Mr. Mnuchin’s intent to recover the $16.5 million, but it provided no fixed schedule of repayment and allowed for repayment “on demand without interest.”

The court also noted that no collateral was given to secure the repayment, and Mr. Tunkl had repaid only $2.5 million of the $44 million debt. Most damningly, the court found that the parties did not conduct themselves as if the transaction were a loan. Mr. Mnuchin wired the funds as a joint investor in the Picasso painting deal, not as a lender, and he expected to recoup his investment through a share of the profits from the resale of the painting. The court cited an April 30, 2018 email from Mr. Tunkl to Mr. Mnuchin detailing the profit split arrangement, which further undermined Mr. Tunkl’s loan argument. The court concluded:

“Nothing in this transaction demonstrates that the $16.5 million was a loan from Mr. Mnuchin to Mr. Tunkl.”

The Court’s Power Play: Asserting Authority Over the IRS

The Tax Court’s opinion in Tunkl is notable not only for its substantive holding but also for its assertion of judicial power over the IRS. The court took pains to emphasize that it was not bound by the formalities of the parties’ agreement but instead looked to the substance of the transaction. This approach aligns with the court’s longstanding role as the final arbiter of tax disputes, a role the Supreme Court has repeatedly affirmed.

The court’s opinion also reflects its willingness to disregard backdated documents and unsubstantiated testimony when determining the true nature of a transaction. By rejecting Mr. Tunkl’s arguments—despite his attempts to retroactively document the transaction as a loan—the court sent a clear message: taxpayers cannot avoid income recognition by manipulating the form of a transaction. This is a powerful tool for the Tax Court, allowing it to pierce through formalities and apply the tax laws based on economic reality.

The Broader Implications: A Warning to Art Dealers and S Corporation Shareholders

The Tunkl decision is a cautionary tale for art dealers and S corporation shareholders who rely on informal agreements to structure their transactions. The court’s ruling underscores the importance of proper documentation and the dangers of relying on oral agreements or backdated documents. For art dealers, the case highlights the risks of co-investment arrangements that lack clear terms for repayment or profit-sharing. For S corporation shareholders, the decision serves as a reminder that funds received by the corporation are taxable income unless they are properly structured as loans or capital contributions.

The Tax Court’s opinion also signals that the IRS and courts will closely scrutinize transactions involving high-value assets, such as art, where the potential for tax avoidance is significant. The court’s willingness to disregard formalities and focus on economic substance means that taxpayers must be meticulous in documenting their transactions to avoid costly disputes with the IRS.

What This Means for Art Dealers and S Corporation Shareholders

The Tax Court’s ruling in Tunkl v. Commissioner (T.C. Memo. 2026-11, filed Sept. 10, 2026) does more than just uphold a $16.5 million deficiency—it reshapes how high-value asset transactions, particularly in the art world, must be structured to avoid immediate tax liability. The court’s holding that the $16.5 million received by Mr. Tunkl constituted gross income under § 61(a)—despite his argument that it was a loan—sends a clear warning to art dealers and S corporation shareholders: informal agreements are a tax disaster waiting to happen. The opinion, written by Judge Albert G. Lauber, emphasizes that the IRS and courts will disregard transactional formalities when the economic reality demonstrates that funds were unconditionally available to the taxpayer, triggering taxable income under the dominion and control doctrine.

For art dealers, the ruling underscores the peril of undocumented transactions. The court rejected Mr. Tunkl’s claim that the $16.5 million was a loan because there was no contemporaneous written agreement, no fixed repayment schedule, and no evidence of a debtor-creditor relationship. This aligns with prior precedent, including Welch v. Commissioner, 204 F.3d 1228 (9th Cir. 2000), where the Ninth Circuit held that advances lacking formal loan structures were taxable compensation. The Tax Court’s decision in Tunkl extends this principle to high-value art transactions, where the potential for tax avoidance is significant. Art dealers who receive funds—whether as deposits, advances, or purported loans—must document the transaction at the time the funds are received with a written agreement, interest terms, and a repayment schedule. Failure to do so risks immediate taxation under § 61(a), as the court will look past the label of the transaction to its economic substance.

S corporation shareholders face a parallel risk. The court’s analysis highlights that funds received by an S corporation and retained by its shareholder are taxable income to the shareholder if the corporation lacks a legitimate business purpose for holding the funds. Under § 1366(a), income flows through to shareholders regardless of whether it is distributed, and the court’s emphasis on dominion and control means that shareholders cannot avoid taxation by leaving funds in the corporate account. The opinion implicitly rejects the argument that funds held by an S corporation are shielded from immediate taxation, reinforcing that shareholder control over corporate funds can trigger taxable income at the shareholder level. This is particularly consequential for art dealers structured as S corporations, where personal use of corporate funds for art purchases or transactions could be recharacterized as constructive dividends or compensation.

The court’s willingness to disregard formalities in favor of economic substance represents a significant exercise of judicial power over the IRS’s traditional deference to taxpayer labeling of transactions. By focusing on dominion and control—a doctrine rooted in James v. United States, 366 U.S. 213 (1961), and Rutkin v. United States, 343 U.S. 130 (1952)—the Tax Court signals that it will pierce the veil of transactional structures where the taxpayer retains unfettered access to funds. This approach aligns with the IRS’s recent enforcement priorities, particularly in high-value asset transactions where the risk of tax avoidance is acute. For future taxpayers, this means that every dollar received must be scrutinized for its tax treatment at the moment of receipt, not after the fact when the IRS comes knocking.

The practical takeaway is stark: document everything, or risk taxation. Art dealers and S corporation shareholders must treat funds received—whether as loans, deposits, or advances—as potentially taxable income unless they can prove otherwise with clear, contemporaneous evidence. The Tax Court’s opinion in Tunkl is not just about one taxpayer’s misfortune; it is a roadmap for IRS scrutiny in an era where high-value asset transactions are increasingly scrutinized. The court’s power to recharacterize transactions based on economic substance over form is now fully on display, and taxpayers who fail to heed this warning will find themselves on the wrong side of a deficiency notice.