EBAY NASDAQ Security breach

eBay

eBay disclosed that compromised employee credentials enabled access to a customer database and asked all users to reset passwords.

1 month vs SPY -10.0 pp Below SPY

-5.0% EBAY vs +5.0% SPY

DisclosureMay 21, 2014 · time unknown
Company’s roleDirect victim
Available data12 months complete
Share typeCommon stock · EBAY

This site shows how share prices moved after an incident became public. It does not prove that the incident caused the move. Company news, sector moves and the wider market can affect every result. Educational only — not investment advice.

Disclosure timing

When could the market react?

The baseline is the last adjusted close before the news was public. The reaction session is the first close afterward.

  1. 01Baseline sessionMay 20, 2014

    Normalized to 100 for both EBAY and SPY.

  2. 02Public disclosureMay 21, 2014 · time unknown

    Publication time is not documented; lower timing precision.

  3. 03First reaction closeMay 21, 2014

    -0.2% company total return versus +0.8% for SPY; -1.0 pp market-relative return.

Disclosure time is unknown; the previous session close is used as baseline.

Time windows

Company vs SPY

Each row uses the last trading session on or before its target date. “Market-relative” is the company return minus the SPY return, in percentage points.

Returns measured from the shared baseline session
WindowEndpointEBAYSPYMarket-relativeSignal
First reaction May 21, 2014 -0.2% +0.8% -1.0 pp Below SPY
+7 days May 28, 2014 -3.0% +2.0% -5.1 pp Below SPY
+1 month Jun 20, 2014 -5.0% +5.0% -10.0 pp Below SPY
+3 months Aug 21, 2014 +7.6% +6.9% +0.7 pp Above SPY
+6 months Nov 21, 2014 +4.7% +11.2% -6.5 pp Below SPY
+12 months May 21, 2015 +15.0% +16.1% -1.1 pp Below SPY
Compare with current catalog aggregates
WindowThis caseCatalog medianCatalog meann
First reaction-1.0 pp-0.8 pp-1.5 pp30
+7 days-5.1 pp-2.0 pp-4.0 pp30
+1 month-10.0 pp-6.6 pp-6.8 pp30
+3 months+0.7 pp-5.1 pp-6.6 pp30
+6 months-6.5 pp-5.6 pp-7.5 pp30
+12 months-1.1 pp-3.7 pp-10.1 pp30

Normalized total return

EBAY compared with SPY

Baseline session = 100. Adjusted close reflects splits and reinvested distributions.

eBay had +15.0% company total return versus +16.1% for SPY; -1.1 pp market-relative return. The chart shows normalized adjusted-close performance for up to 24 months.

View tabular chart fallback
Representative normalized chart points, sampled approximately monthly
DateEBAYSPY
May 20, 2014100.0100.0
Jun 19, 201495.5104.8
Jul 21, 201499.5105.7
Aug 19, 2014103.4106.3
Sep 18, 2014101.4108.1
Oct 17, 201492.3101.4
Nov 17, 2014105.5110.0
Dec 17, 2014108.6108.6
Jan 20, 2015103.3109.4
Feb 19, 2015111.0113.6
Mar 20, 2015111.5114.4
Apr 21, 2015108.6113.9
May 20, 2015113.8115.7
Jun 19, 2015117.7115.2
Jul 21, 2015130.8115.7
Aug 19, 2015125.4113.8
Sep 18, 2015119.0107.3
Oct 19, 2015112.3111.7
Nov 17, 2015130.1112.8
Dec 17, 2015128.3112.5
Jan 20, 2016118.1102.6
Feb 19, 2016108.9106.1
Mar 21, 2016111.3113.6
Apr 20, 2016112.8116.7
May 19, 2016107.1113.4
May 20, 2016108.1114.1

Price recovery

Recovered

Here, recovery only means that adjusted close reached the baseline again. It does not mean every effect of the incident ended.

State
Recovered
Initial trough
-3.0% on May 28, 2014
Recovery close
May 23, 2014
Calendar days
2
Observation cap
24 months after disclosure

Hypothetical $1,000

What would $1,000 have looked like?

Compare $1,000 in EBAY with $1,000 in SPY, bought and measured on the same dates.

EBAY value $1,054 eBay
SPY value $1,094 US market benchmark
Difference vs SPY -$40 Observed result

Entry May 27, 2014 Exit Nov 26, 2014

Uses fractional shares and adjusted close. Leaves out taxes, fees and slippage. The holding period starts on the purchase date. This is a historical illustration, not an investment strategy.

Case note

eBay reported that attackers had used compromised employee credentials to enter its corporate network and access a database containing encrypted passwords and other non-financial customer data. It asked its entire user base to change passwords.

The broad mandatory reset and customer-data exposure satisfy the systemic and measurable-impact tests. The record uses date precision because the archived company release does not provide a dependable market-timing timestamp.

Evidence

Sources and case review

We qualify each case before checking its price results. These links support the disclosure date, listing, incident and business impact.

  1. primary May 21, 2014
    eBay Inc. to ask eBay users to change passwords eBay Inc. Supports: Disclosure, Listing, Impact, Description
  2. Listing evidenceChecked Jul 20, 2026
    eBay asks users to change passwords eBay Inc. The event announcement identifies eBay as Nasdaq-listed under EBAY at disclosure.

Why it is included. The issuer directly suffered the compromise, publicly fixed the disclosure date and required a platform-wide password reset after a customer database was accessed. Reviewed Jul 20, 2026.