When a company sued by no one else responds to a short-seller report by suing the messenger, the market has learned to treat that lawsuit as a confession dressed as a denial. Two studies covering nearly three decades of activist short campaigns land on the same uncomfortable finding: the firms that litigate underperform the firms that do not, and they underperform badly. The reflex read is that lawsuits scare off buyers or signal a company under siege. That gets the causation backwards. The lawsuit is not what breaks the stock. It is the observable signal that a firm which could have refuted the allegations cheaply chose instead to spend money and time on a filing that rarely wins.
What the Studies Actually Measured
Brendel and Ryans, working through 421 short-seller publications between 1996 and 2018, found that only 6% of targeted companies sued the short seller. That scarcity matters, because it means litigation is not the default corporate response. It is a selected behavior. Among those few that sued, 50% were eventually delisted, against 25% for the full target population. Over the year following the report, the suing firms averaged a cumulative abnormal return of -46%, while all targets averaged -34%. The litigators started worse and ended worse.
The commissioned update from Grizzly Research extends the window to 2018 through August 2025, covering 1,100 activist publications against 906 firms. Twenty-four of those firms sued the publisher. In all twenty-four, the share price failed to recover against the S&P 500 over the long term. The suing cohort averaged a -72.0% return against the index and -54.4% in absolute terms. Firms that did not sue returned -29.4% against the index but a positive 15.8% in absolute terms. The gap is not marginal. Twelve of the twenty-four suing firms underperformed the index by more than 80%.
The single most important number in the update is the one that survives a control most readers would reach for. Strip out the window between the report and the lawsuit, so that none of the initial post-report decline is credited to the litigation, and the suing firms still underperform the index by 66.0% measured from the filing date forward. The collapse continues after the lawsuit, not just before it. That rules out the simplest counter-explanation, that these stocks were already falling and the suit was incidental.
The Selection Mechanism, Not the Litigation
The temptation is to model the lawsuit as a cause: a suit signals distress, distress deters buyers, the stock falls. That model is thin, because a company with a clean set of books has a cheaper and faster remedy than litigation. It can publish the contract, the bank statement, the audited reconciliation, the customer confirmation. A genuine refutation is a document, not a docket entry.
Litigation is what a firm reaches for when the document does not exist or does not say what management needs it to say. The suit substitutes process for proof. It buys a headline that says the company is fighting back, and it defers the moment when the specific allegation must be answered on its merits. Discovery, if the case ever reaches it, runs the wrong direction for a firm with something to hide. This is why both studies converge on the same interpretation: the lawsuit is predominantly a bluffing strategy. Brendel and Ryans framed it that way, and the updated data reinforces it. Suing firms rarely achieve profitable settlements, and firms can and do refute false allegations without any legal filing at all.
Read this way, the lawsuit is not an input to the stock's decline. It is an output of the same underlying condition that is driving the decline. The condition is that the allegations are substantially harder to rebut than to assert. The suit is the visible symptom; the unrebuttable allegation is the disease. The market is not reacting to the filing. It is reading the filing as evidence about what management could not do instead.
Why the Signal Persists for Years
A one-year abnormal return could be noise or overreaction that later corrects. The persistence in the Grizzly data is what makes the signal analytically interesting. The suing cohort's underperformance against the index reaches roughly 80% on average around six years after publication. Stocks do not stay wrong against a benchmark for six years because sentiment soured. They stay wrong because the fundamental problem the short seller identified was real and eventually surfaced in delistings, restatements, or terminal declines.
That time structure is the tell that separates a fundamental signal from a behavioral one. Behavioral mispricings mean-revert. A fraud, an accounting fiction, or a business that cannot sustain its reported economics does not mean-revert. It resolves. The lawsuit marks the firms where resolution was most likely to be adverse, which is precisely why those firms chose the filing over the disclosure.
Where the Read Could Break
The strongest objection is survivorship and selection running the other way. Small, thinly traded, already-troubled firms may be both more likely to sue, out of desperation, and more likely to fall regardless of the suit. If litigation is simply a marker of firms that were doomed for independent reasons, then the lawsuit predicts nothing that market cap, liquidity, and prior returns would not predict on their own. Neither study, as summarized here, fully isolates the litigation decision from the firm characteristics that select for it, and that is a genuine limit on how far the causal language can stretch.
There is a second limit worth stating plainly. Twenty-four firms in the updated cohort is a small sample. When all twenty-four move the same direction, the direction is convincing, but the magnitude estimates carry wide error bars, and a handful of catastrophic delistings can dominate an average expressed against a rising index. The -72.0% figure should be read as a strong directional finding, not a precise expected value for the next firm that sues.
What the persistence result does, though, is blunt the pure-selection objection. If the effect were entirely driven by pre-existing weakness, stripping the report-to-filing window should erase most of it. It does not. Sixty-six percentage points of underperformance accrue after the filing date. That is consistent with the interpretation that the allegation was fundamentally sound and continued to play out, and it is hard to reconcile with a story where the suit was merely incidental to a decline that had already fully priced in.
The Condition That Confirms or Invalidates the View
The practical read is narrow and testable. When a target of an activist short report responds with a lawsuit rather than a document, treat the lawsuit as new information that increases, not decreases, the probability that the allegation was material. The base rate is stark: in the updated sample, zero of twenty-four suing firms recovered against the index over the long term. A management team confident in its books answers with the books.
The view inverts on a single observable. If a suing firm publishes, alongside its complaint, the specific contemporaneous evidence that directly rebuts the short seller's central factual claim, the signal weakens sharply, because the firm is no longer substituting process for proof. The lawsuit as a bluffing strategy depends on the absence of that evidence. Its presence would be the counterexample the pattern does not yet contain. Until a suing firm produces it and recovers, the cleaner reading is that the docket entry is a confession the market has already learned to price.
