The Real Cost of "Move Fast" DD

Competitive deal markets create pressure to accelerate timelines. Buyers rush through due diligence to outpace rivals, secure targets before regulatory windows close, or avoid being outbid. The cost of delay feels immediate; the cost of inadequate DD materializes later.

Research analyzing 40,000 M&A deals over 40 years found that 70 to 75% of acquisitions fail to achieve their stated objectives. Bain surveys indicate only 30% of major deals create significant shareholder value. Per Bain, half of senior executives with M&A responsibilities report their due diligence process overlooked major problems, and two-thirds say their approach routinely overestimated synergies.

Rushed DD leaves critical areas under-assessed: financial discrepancies, legal liabilities, cultural misalignment, and operational dependencies. Standard M&A due diligence runs 60 to 90 days from letter of intent to close, with the bulk of document review in days 8-45. Compressing that window reduces the time available for customer verification, competitive analysis, and independent fieldwork.

Bain recommends diligence that is "faster, deeper, and more focused than competitors" but emphasizes that winning acquirers conduct independent verification rather than relying on target-provided data. Speed without depth produces reports that document what was requested, not what was verified. The result: missed red flags that surface post-close.

The 1998 merger of Daimler-Benz and Chrysler illustrates how inadequate cultural due diligence compounds over time. Announced as a "merger of equals" with $132B in combined revenue, the deal promised $1.4B in savings. Instead, the two cultures proved incompatible: formal German engineering versus American "can-do cowboy" culture. Daimler executives reportedly refused to be seen in Chrysler vehicles. Integration never materialized; the companies operated as separate entities with consolidated balance sheets. Daimler sold Chrysler in 2007, abandoning the combined enterprise.

Cultural integration was not a surprise risk. It was a known variable that required deeper assessment than deal speed permitted. The cautionary tale applies beyond automotives: when haste truncates the diligence that would surface cultural and operational misalignment, the cost appears in integration failures and divestiture discounts.

The case against "move fast" DD is strong, but it is not absolute. There are situations where compressed timelines are justified and even necessary.

Bain documents a leveraged buyout firm that completed comprehensive due diligence in four weeks, enabling a preemptive bid. The result: EBITDA more than doubled within two years post-acquisition. The difference was not skipping diligence but conducting it "faster, deeper, and more focused." The firm had already begun diligence on priority targets before formal processes started.

When speed works, it is usually because: (1) the acquirer has ongoing diligence capacity rather than starting from zero at deal kickoff, (2) the target is in a sector or geography the acquirer already knows well, (3) integration planning happens during diligence rather than after close, and (4) the deal thesis is narrow enough that focused verification can be completed quickly. In contested auctions or time-sensitive situations, the alternative to fast diligence is often no deal, not a better deal.

The key distinction: speed that comes from prior preparation and focused scope is different from speed that truncates verification. The former can succeed. The latter produces the statistics cited above.

Before accepting a compressed DD timeline, ask: Is the pressure structural or self-imposed? Can we start diligence before the formal process? Do we have sector depth that reduces the learning curve? Are we planning integration during diligence or deferring it? Companies with dedicated M&A organizations and strong executive oversight tend to create more value than less-experienced acquirers, in part because they have the capacity to move fast without moving carelessly.

The "move fast" mantra becomes dangerous when it substitutes for preparation. The alternative is not infinite diligence; it is diligence calibrated to deal risk and supported by prior work. When that calibration is missing, the statistics speak for themselves.