The gentleman's agreement that started a £112 billion war: Vodafone's hostile takeover of Mannesmann, 1999–2000

The gentleman's agreement that started a £112 billion war: Vodafone's hostile takeover of Mannesmann, 1999–2000

In October 1999, Mannesmann's acquisition of Orange gave Vodafone CEO Chris Gent the narrative trigger he needed: by framing the deal as a violation of an unwritten 'gentleman's agreement,' he positioned an aggressive cross-border raid as a proportionate response. This case traces the three-month battle from hostile rejection to 4 a.m. supervisory board acceptance, explains why Germany's co-determination system — widely assumed to be impenetrable — functioned as a negotiating table rather than a veto, and shows how the EC's Orange divestiture requirement aligned with Vodafone's own preferences rather than constraining them. The post-deal verdict: a £28 billion goodwill write-down in 2006, triggered by German MVNO competition that no internal model had projected at the pace it materialized.

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2026/5/26 · 2:20
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On the morning of November 14, 1999, Vodafone AirTouch CEO Chris Gent sent a letter to Mannesmann CEO Klaus Esser proposing a friendly merger. Esser's board rejected it the same day. That rejection set in motion the most expensive hostile takeover in corporate history — a £112 billion (~€180 billion) all-share offer that played out across boardrooms in Düsseldorf, London, and Brussels over the following three months 1 2. The trigger, as Gent described it publicly, was a single corporate act by Mannesmann two weeks earlier: its acquisition of Orange, the UK mobile operator. That deal, Gent argued, had broken the unwritten "gentleman's agreement" that Vodafone and Mannesmann would not compete in each other's home markets 3. Esser disputed that framing. The war that followed would take three months, consume the attention of the European Commission, and end with the supervisory board of Germany's most storied industrial conglomerate voting to accept Vodafone's terms at 4 a.m. on February 3, 2000 1.

Parties and stakes

Vodafone AirTouch (acquirer)Mannesmann AG (target)European CommissionGerman labour & co-determination system
Core objectiveAcquire Mannesmann's pan-European mobile footprint — particularly D2 in Germany and Omnitel in Italy — to build a self-owned network across 8 EU member statesPreserve independence; maximize price if independence proved untenableEnsure competitive mobile and pan-European seamless services markets; prevent creation of a dominant operator in UK and BelgiumProtect jobs and co-determination rights for workers in Mannesmann's industrial divisions
LeverageVodafone already owned 34.8% of Mannesmann pre-bid; rising stock price amplified share-exchange value; direct approach to Mannesmann shareholders bypassed the board 3Traditional German ownership structure (cross-holdings, bank relationships); supervisory board with labour representatives; national political supportLegal authority to block or condition the merger under EU Merger Regulation No 4064/89; power to define relevant markets 4Half the Mannesmann supervisory board seats held by employee representatives under German co-determination (Mitbestimmung)
BATNAContinue minority ownership of Mannesmann — financially viable but strategically exposed to a future rival acquiring D2 and OmnitelSeek a white-knight acquirer or pursue standalone strategies using Orange as a growth engineIssue a Phase 2 investigation and negotiate divestitures — not inclined to block outright when structural remedies would suffice 4Strike action and political lobbying — the playbook from the 1997 Krupp-Thyssen hostile bid that mobilized mass protests across Germany
Hidden preferenceStrongly preferred a friendly deal: hostile bids are expensive, slow, and distract management 3Esser privately knew that independence required a sustainable standalone strategy — and Orange, purchased just weeks earlier, made that strategy more plausible but also more contestedPhase 1 clearance with pre-negotiated remedies was operationally preferable to a Phase 2 blockade 4Labour representatives ultimately shared management's preference for unlocking value in Mannesmann's telecom assets — separating them from the steel and engineering divisions both workers and shareholders had come to see as a drag

Background and context

By the late 1990s, European mobile telecommunications had become the fastest-growing industry on the continent. Subscriber bases were doubling every eighteen months. Pan-European roaming was still cumbersome, requiring separate SIM cards or bilateral contracts, but the prize for any operator that could offer seamless service across borders was enormous — particularly to the corporate clients who spent the most on roaming.
Mannesmann was, by heritage, a German engineering and steel company founded in 1890. But through the 1990s its CEO Joachim Funk — and then Esser — had pursued an aggressive pivot into telecommunications. By October 1999, Mannesmann's crown asset was D2, its German mobile operation with a 34% domestic market share, and it held majority stakes in Omnitel in Italy and minority positions in France (SFR), Belgium (KPN Orange), Austria (tele.ring), and Switzerland 4. The October 1999 acquisition of Orange in the UK — bought from Hutchison Whampoa for approximately £19.8 billion — was intended to be the capstone of that European strategy 2.
Vodafone AirTouch was itself the product of a 1999 merger between Vodafone (UK) and AirTouch Communications (US), which had also given Vodafone a 34.8% stake in Mannesmann and a September 1999 deal to combine its US wireless assets with Bell Atlantic into what would become Verizon 1. The Verizon transaction freed Vodafone from its US obligations and sharpened its focus on Europe. With D2 in Germany and Omnitel in Italy beyond its reach, Vodafone could not offer corporate clients the self-owned pan-European network that was becoming the industry's defining competitive asset. The Orange acquisition — Mannesmann's new UK mobile business — made that gap more urgent.
The deeper structural context mattered. German corporate governance in 1999 retained most of the features of its postwar stakeholder model: supervisory boards with mandatory labour representation under the 1976 Mitbestimmungsgesetz, concentrated cross-shareholdings among major banks, and a tradition of private block-sale negotiations rather than open market contests for corporate control 3. Between 1995 and 1999, only two hostile takeover bids had been launched in Germany 3. The 1997 Krupp hostile bid for Thyssen had provoked strikes, street protests, and intervention from Chancellor Helmut Kohl before collapsing. Germany was, in the conventional wisdom of 1999, immune to the Anglo-Saxon market for corporate control.
That immunity was more fragile than it appeared.

The negotiation dynamics

Power asymmetries

Vodafone's most important structural advantage was not financial — it was informational and temporal. Having owned 34.8% of Mannesmann through its AirTouch inheritance, Vodafone had years of insight into Mannesmann's strategy, management style, and investor base. Crucially, Vodafone could observe that Mannesmann's shareholder register had shifted: by 1999, international institutional investors held approximately 44% of Mannesmann stock 3. These investors — Anglo-American pension funds, hedge funds, and asset managers — were far more receptive to a cash-or-stock premium than to arguments about German industrial heritage or employment stability.
Mannesmann's theoretical defenses were substantial. The supervisory board, with its labour representatives, had the constitutional authority to block a board recommendation in favour of accepting any bid. German banks, traditionally Mannesmann's institutional anchors, could have deployed cross-holding relationships to make the hostile bid politically costly. Employee shareholders held approximately 7.5% of the equity 3.
None of these defenses held. The banks — Deutsche Bank in particular — had spent the previous decade transforming themselves from relationship lenders to investment banking competitors. Deutsche Bank's CEO Josef Ackermann sat on the Mannesmann supervisory board, not as a defensive anchor but as a representative of a shareholder interest that tilted toward unlocking value 3. Employee shareholders saw Mannesmann's stock rise 120% between October 1999 and February 2000 — generating approximately €10 billion in gains for Mannesmann shareholders overall — and most chose to sell rather than hold out 3. The 1998 KonTraG law had already repealed most dual-class voting arrangements that German companies had historically used to repel hostile bids 3.

Information gaps and the framing battle

From the moment Vodafone launched its hostile offer, the negotiation was fought on two fronts: price and narrative. On price, Vodafone held the advantage — it controlled the share-exchange ratio and could ratchet its offer whenever Mannesmann's institutional investors signalled wavering. On narrative, Esser mounted an aggressive defense, arguing to German media, politicians, and the supervisory board that Mannesmann as an independent entity — now with Orange as a UK anchor — would generate more long-term value than Vodafone's all-share consideration.
Esser's narrative had one structural weakness: it required investors to trust a standalone valuation that was inherently speculative. Vodafone's offer required them only to trust a stock-for-stock exchange ratio in a rising market. As Mannesmann's stock rose in anticipation of an improved bid, every increase in Vodafone's offer price simultaneously validated the logic of accepting the deal.

Coalition dynamics

The decisive coalition shift was the labour representatives on Mannesmann's supervisory board. Unlike the 1997 Krupp-Thyssen episode — where steelworkers had mobilized 30,000 people in street protests — Mannesmann's workers showed no similar appetite for resistance 3. The reason was structural: Mannesmann's blue-collar industrial workforce had watched the company spend a decade diverting investment from their divisions into telecommunications. The bid offered a vehicle to crystallize that telecom value and potentially spin off or recapitalize the industrial businesses. Labour representatives on the supervisory board ultimately voted in favour of accepting the Vodafone offer — their agreement was essential under German co-determination rules — in exchange for employment protection commitments covering the industrial workforce 3.
The apparent paradox — Germany's strongest institutional defense against hostile takeover became a vehicle for enabling one — resolved when the interests of different stakeholders were disaggregated. Labour did not oppose the deal. Banks did not block it. The political firestorm that had killed Krupp-Thyssen never materialized at the same scale.
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Key decision points

Decision 1: Vodafone's October 1999 framing choice

When Mannesmann announced its Orange acquisition, Vodafone faced a choice about how to respond publicly. Gent framed it as a breach — "breaking the gentleman's agreement" — rather than as a competitive response to a market event. That framing was strategically calculated: it positioned Vodafone as the aggrieved party responding to provocation, rather than as an aggressor launching an unprovoked raid on a German industrial giant.
The framing had consequences. It gave Vodafone a moral logic it could repeat to Mannesmann's institutional shareholders ("Esser broke the rules first"), it undercut Esser's political defense ("Mannesmann is the victim of Anglo-Saxon aggression"), and it provided a narrative basis for the hostile offer that was difficult for German regulators or politicians to contest without implicitly endorsing Mannesmann's Orange acquisition.

Decision 2: Esser's decision to reject the initial approach

Esser's rejection of Gent's November 14 approach was rational under the strategic logic of a German CEO in 1999. The German takeover code did not yet require boards to put offers to shareholders directly. Mannesmann's defenses — co-determination, bank relationships, political support — appeared formidable. The Orange acquisition had just closed, lending Esser a credible standalone story. Accepting or even engaging with the approach would have signalled weakness.
The error was underestimating the speed at which Vodafone could erode those defenses by going directly to shareholders. The hostile offer, launched November 19, 1999, gave Mannesmann's international institutional investors a concrete alternative price signal — one that, as Vodafone continued raising its bid, made Esser's standalone valuation increasingly hard to defend without independent financial analysis of equal credibility.

Decision 3: The exchange ratio escalation

The final agreed exchange ratio of 53.7 Vodafone shares per Mannesmann share was not the opening number 1 2. Vodafone raised its offer multiple times during the three-month hostile phase in response to Mannesmann's institutional investors and the advice of its own bankers (Goldman Sachs led the Vodafone advisory effort 5). The decision to escalate to a ratio implying a transaction value of £112 billion was driven by a specific calculus: at that ratio, even the most sceptical Mannesmann institutional investor faced a bid premium too large to reject on fiduciary grounds, while Vodafone's own rising stock price meant the actual dilution for Vodafone shareholders was being carried in part by the broader technology/telecom market rally.
The choice to use an all-share rather than cash structure was equally deliberate. It avoided the leverage required for a £112 billion cash deal, transferred valuation risk to Mannesmann shareholders (who now held Vodafone shares), and was structured as a tax-free exchange — a feature designed to make the deal more palatable to German shareholders who faced significant embedded gains in their Mannesmann positions 3.

Decision 4: Esser's negotiation of the terms

Once Esser concluded in late January 2000 that the deal was inevitable — Mannesmann's institutional shareholders were signalling acceptance — the negotiation shifted to extraction. The Mannesmann supervisory board's February 3 acceptance of Vodafone's offer included employment protection commitments for industrial workers, board representation guarantees, and — most controversially — executive compensation arrangements. Esser himself received approximately €30 million in recognition payments, approved by the supervisory board and characterized as a reward for his stewardship through the takeover defense 3. Other executives received similar awards. The payments would become the central issue in a subsequent criminal trial.

How it ended

On February 3, 2000, at approximately 4 a.m., the Mannesmann supervisory board voted to accept Vodafone's revised all-share offer. The transaction closed on March 27, 2000, with 98.62% of Mannesmann shareholders tendering their shares 4. The acceptance rate left almost no room for dissent.
Value distribution was asymmetric. Mannesmann shareholders captured approximately €10 billion in gains from the 120% stock price rise during the hostile period 3. Vodafone, paying in its own stock at the peak of the telecom bubble, was handing over shares at their highest-ever valuation. Whether that was overpayment or market-rate currency would depend entirely on whether Vodafone's stock price — and the underlying mobile assets — could sustain their 2000 levels.
The European Commission cleared the merger on April 12, 2000 under Article 6(2) of Regulation No 4064/89 — a Phase 1, non-opposition decision, not a full Phase 2 investigation 4. The Commission had identified three markets raising "serious doubts": UK national mobile services, Belgian mobile services, and an emerging pan-European seamless services market. The merged entity would have controlled two of four UK operators (Vodafone's 33.2% share plus Orange's 20.4%), a combined 53.6% — twice the size of BT Cellnet 4. In Belgium, the merged entity would have held nearly 70% 4. And on the pan-European dimension, Vodafone would have held controlling interests in 8 member states, joint control in 3 more, with a subscriber base exceeding 40 million and a European market share above 30% 4. Third parties estimated competitors would need 3–5 years and 30–60 new inter-operator contracts to replicate that footprint 4.
The Commission cleared the deal on two undertakings: a complete divestiture of Orange, and a three-year commitment to non-discriminatory roaming access for third parties 4. The Orange brand was subsequently sold to France Télécom for approximately €40 billion in May 2000 1 — a divestiture that, as discussed below, Vodafone was content to make.
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Vodafone's management described the post-merger ambition in Gent's own words to Fortune magazine in March 2000: the combined entity would have "an unrivalled power to sell seamless pan-European services with pan-European rates" 4. Over the following decade, Vodafone subsequently divested Mannesmann's remaining industrial and non-mobile assets, recovering more than €14 billion in proceeds 3.

Post-deal reality

The bonus trial

The executive compensation arrangements approved by the Mannesmann supervisory board on the day of the deal's acceptance became the focus of a criminal prosecution in Germany. In 2004, Esser, Ackermann, and other supervisory board members were indicted at the Landgericht Düsseldorf on charges of breach of trust (Untreue) under §266 of the German Criminal Code — the allegation being that the approximately €30 million in recognition payments to Esser and colleagues could not be justified as legitimate compensation for services rendered and thus constituted a misappropriation of shareholder funds 3.
Ackermann's courtroom V-for-victory gesture — photographed at the Düsseldorf courthouse in January 2004 — became one of the most widely reproduced images in German corporate governance history, widely interpreted as a defiant display of executive privilege during a trial about executive excess. The Landgericht acquitted the defendants in 2004. The Bundesgerichtshof (Germany's Federal Supreme Court) reversed the acquittal in 2005. The defendants were acquitted again on final retrial in 2006 3.
The trial's ultimate legal outcome — acquittal — confirmed that the payments had been within the supervisory board's authority. But the decade-long saga accelerated German corporate governance reforms on executive compensation transparency, supervisory board independence, and the definition of shareholder primacy duties.

The goodwill write-down

The operational verdict on the deal arrived in February 2006. Vodafone announced a £28 billion asset impairment charge — one of the largest write-downs in European corporate history — against the goodwill it had recorded at the time of the Mannesmann acquisition 6. The FY2002 annual report had already recorded £13.5 billion in goodwill amortization and £6 billion in exceptional impairments on non-mobile assets; the CEO had explicitly stated at that time: "We have no doubt in the continued growth potential of the business, which is why we have not impaired the carrying value of our controlled mobile assets." 7 The 2006 reversal of that position was total.
CEO Arun Sarin — who had replaced Gent — attributed the impairment to the German mobile market specifically: "The UK market has been a competitive market for many years. But in Germany in the last year or so 10 important MVNOs have come to play, prices are falling quite dramatically." 6 At the time of the Mannesmann acquisition, Germany had four mobile operators. By 2005, ten MVNOs (mobile virtual network operators) had entered the German market, competing aggressively on price 6.
The write-down raised a pointed retrospective question: if the German MVNO market's competitive structure was a material driver of asset value, why had it not been modelled as a scenario in the 1999–2000 deal due diligence? The question has no clean answer. MVNO proliferation was visible as a policy direction in German telecommunications regulation well before 2000, but its speed and price impact after the acquisition exceeded any internal Vodafone forecast that has entered the public record.
A financial desk showing reports with steep downward charts, overcast European city skyline visible through floor-to-ceiling windows
In February 2006, Vodafone announced a £28 billion write-down on goodwill recorded at the Mannesmann acquisition — CEO Arun Sarin cited the explosion of German MVNOs from 4 to 10 operators, which drove prices "falling quite dramatically" 6

The structural legacy

Höpner and Jackson's 2006 analysis of the case's institutional effects found that the Mannesmann takeover — rather than remaining an exception — inaugurated a sustained change in the German market for corporate control. Between 2000 and 2005, Germany saw 13 hostile takeover bids, of which 9 succeeded; in the prior five years, only 2 had been attempted 3. The change was not produced by a single legislative reform — Germany's takeover act (Wertpapiererwerbs- und Übernahmegesetz) was not passed until 2002 — but by complementary shifts in bank strategy, co-determination norms, accounting standards, and investor composition that had been accumulating through the 1990s 3. Vodafone found the seam; others followed through it.
For Mannesmann employees in the telecommunications division, the deal's human consequences were direct. The German telecom headcount fell from 14,778 in 1998 to 10,124 by 2006 — a 32% reduction — while Vodafone restructured and eventually sold or rationalized the industrial divisions 3.

Frameworks you can use

The gentleman's agreement as a reversible trigger

Informal understandings — "gentlemen's agreements," strategic truces, no-compete courtesies — are common in industries where major players have overlapping interests and need to coexist. What the Mannesmann case illustrates is that these agreements carry no enforcement mechanism, and their violation can serve as an aggressor's justification as readily as a victim's grievance.
Gent's framing of the Orange acquisition as a breach was effective precisely because it reversed the moral polarity. Vodafone, a company that was about to conduct an aggressive hostile raid across national borders, became — in its own telling — the wronged party responding proportionately to provocation. Esser, who had expanded his company's footprint in a commercially rational way, became the one who "started it."
The actionable principle for deal-makers: if your company relies on any informal understanding with a counterpart to constrain their competitive behaviour, either formalize it with a written non-compete (specifying term, geography, and enforcement mechanism) or assume it will not hold the moment the counterpart sees a better strategic option. Conversely, if you are entering an arrangement where your own future freedom to act might be retroactively characterized as a breach, document the scope of any understanding explicitly — in writing — before the relationship begins. The "gentleman's agreement" that Gent invoked in November 1999 had no written form anyone has produced.

Regulatory divestiture as strategic alignment

The European Commission's Orange divestiture requirement is routinely discussed as a regulatory cost imposed on Vodafone as a condition of clearance. The actual dynamics were more complex. Orange — a UK operator Mannesmann had just purchased — was precisely the asset Vodafone did not want to own: it competed directly with Vodafone UK, and integrating two UK operators would have created internal conflict, customer overlap, and staff duplication. The divestiture condition aligned almost perfectly with Vodafone's own strategic preferences.
By offering Orange as a remedy voluntarily in its pre-notification discussions with the Commission, Vodafone converted a potential Phase 2 investigation — which could have delayed or blocked the merger for 6–12 months — into a Phase 1 clearance completed within 90 days of notification 4. The sale of Orange to France Télécom for ~€40 billion also recovered significant value from an asset Vodafone had inherited without seeking 1.
The framework for deal-makers: in complex cross-border M&A, regulators and acquirers often want to achieve the same structural outcome — the question is whether the acquirer identifies that alignment early enough to offer it voluntarily (gaining speed and goodwill) or waits until a formal remedy is imposed (losing time and control over the divestiture process and price). A pre-clearance audit that maps which of the target's assets the acquirer genuinely does not want — and which of those are likely to raise competition concerns — can transform regulatory risk from a late-stage threat into an early-stage tool.

The hostile-to-friendly conversion: how the pivot actually happened

The transition from hostile to friendly is often described as a sudden capitulation. The Mannesmann case shows it was a structured negotiation with several distinct stages.
Stage one was public pressure: Vodafone's direct-to-shareholder offer gave institutional investors a concrete alternative valuation, forcing Mannesmann's board to produce a credible counter-narrative. Stage two was isolation: as each potential defensive coalition member — the banks, the politicians, the workers — concluded that their own interests were better served by the deal than by resisting it, Esser's negotiating leverage narrowed from a broad stakeholder coalition to the specific terms of the supervisory board's final vote. Stage three was extraction: once the supervisory board accepted that the deal would happen, the negotiation shifted to what Mannesmann's board and management could extract — employment protections for industrial workers, board representation, and the executive compensation that would later trigger criminal prosecution.
The analytical lesson is that the hostile-to-friendly conversion should not be read as management capitulating — it should be read as management shifting from one negotiation (blocking the deal) to a different negotiation (maximizing the terms of acceptance). Esser did not simply give up. He extracted considerable concessions, including conditions protecting the industrial workforce, which were the primary interest of the labour representatives whose vote was constitutionally necessary. The final supervisory board acceptance was not a defeat; it was the outcome of a second-round negotiation that Esser conducted from a weakened but not powerless position.

The all-share bubble as bid currency — and its aftermath

Vodafone paid with its own stock at the peak of the TMT (technology, media, telecommunications) bubble. The 53.7:1 exchange ratio 1 valued Mannesmann in Vodafone shares whose market price reflected investor expectations for a sector whose multiple had detached from any cashflow-based valuation discipline. When the bubble deflated — Vodafone's share price fell sharply through 2001 and 2002 — the implied purchase price fell with it. The £28 billion goodwill write-down in 2006 was, in part, the accounting recognition of an overpayment that had been visible in any conservative discounted-cash-flow model applied to the German mobile market in early 2000 6 7.
The principle transfers directly: all-stock acquisitions during market manias are cheaper in headline currency but carry embedded valuation risk that materializes when the acquirer's own stock normalizes. Target shareholders who accept stock rather than cash are, in effect, making a bet on the acquirer's long-term standalone performance. For Mannesmann shareholders who tendered in February 2000 and held their Vodafone stock through the subsequent decline, the 120% pre-deal run-up was partially erased. For those who sold immediately on receiving Vodafone shares, the deal worked. Timing, not deal structure, determined who captured value.
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What to remember

  • Informal strategic truces are reversible — and their breach can be reframed as a launching justification. Vodafone's "gentleman's agreement" argument gave the aggressor a moral platform, reversed the victim narrative, and complicated Mannesmann's political defense. Any cross-border business relationship that depends on an informal no-compete understanding is a potential hostile-bid trigger waiting for the right moment. Document the understanding formally, or assume it will not hold.
  • Germany's co-determination system was not a barrier to the hostile takeover — it was a negotiating table. Labour representatives on the Mannesmann supervisory board did not mobilize mass resistance as they had in 1997 at Thyssen. They negotiated employment protections and voted in favour of acceptance. The lesson for deal-makers approaching stakeholder-governance systems: do not model co-determination as a monolithic veto. Map each stakeholder group's specific interests and identify where those interests converge with the deal's logic. Where they converge, co-determination becomes an enabler rather than a blocker.
  • Regulatory divestiture can be a strategic tool, not just a cost. Vodafone did not want Orange. The EC's divestiture condition aligned with Vodafone's own strategic preferences and enabled a Phase 1 clearance in 87 days. Deal-makers who identify, pre-notification, which of their target's assets they genuinely do not want — and which of those are likely to raise competition concerns — can offer voluntary remedies that accelerate clearance and recover value from unwanted assets.
  • All-stock bids at market peaks transfer valuation risk to target shareholders but book the risk on the acquirer's balance sheet. Mannesmann shareholders who sold Vodafone stock promptly captured the premium. Those who held Vodafone shares through the TMT correction did not. Vodafone booked a £28 billion goodwill write-down six years later when the German mobile market's competitive intensity exceeded every forecast on record 6. When a deal's justification rests on market-growth projections in a sector trading at bubble multiples, the acquirer's goodwill entries are bets, not valuations.

Cover image: AI-generated editorial illustration

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