CoCounsel,
which
launched
almost
exactly
three
years
ago,
on
March
1,
2023,
as
the
first
AI
legal
assistant
built
on
GPT-4,
today
marked
a
notable
milestone,
reaching
1
million
customers
across
107
countries
and
territories.
Developed
by
legal
research
startup
Casetext,
Thomson
Reuters
acquired
CoCounsel
(and
Casetext)
just
four
months
after
its
release,
for
a
whopping
$650
million
in
cash.
Since
then,
TR
has
expanded
CoCounsel
across
its
product
lines
and
across
professional
verticals,
from
legal
to
risk,
compliance,
tax,
accounting,
audit
and
trade.
Thomson
Reuters
(TSX/Nasdaq:
TRI)
announced
the
milestone
at
an
event
in
San
Francisco
Monday,
framing
it
not
just
as
a
measure
of
growth
but
as
a
signal
of
a
broader
shift
in
how
regulated
industries
are
approaching
artificial
intelligence
—
from
cautious
pilots
and
experiments
to
embedded
production
systems.
“Professionals
are
not
deciding
whether
to
use
AI
anymore,”
said
Steve
Hasker,
TR’s
president
and
chief
executive
officer.
“They
are
deciding
which
AI
they
trust
when
their
reputation
and
their
clients’
data
are
on
the
line.”
The
milestone
comes
as
AI
adoption
among
legal
and
other
regulated
professionals
has
moved
decisively
past
the
experimentation
phase,
TR
says.
Firms
and
corporations
are
no
longer
asking
whether
AI
belongs
in
high-stakes
workflows
—
they
are
choosing
which
systems
can
actually
meet
the
standards
those
workflows
demand.
AI
for
Regulated
Work
While
CoCounsel
started
as
a
standalone
chat
interface,
TRThe
company
has
emphasized
that
general-purpose
AI,
however
capable,
falls
short
in
professional
environments
where
outputs
must
withstand
courtroom
scrutiny,
regulatory
review
or
audit
proceedings.
CoCounsel
is
designed
specifically
for
those
contexts,
TR
says,
grounding
its
outputs
in
editorially
refined
legal
and
tax
content
developed
over
175
years
and
validated
by
more
than
4,500
TR
subject-matter
experts
across
legal,
tax
and
compliance
domains.
While
CoCounsel
started
as
a
standalone
chat
interface,
TR
has
integrated
it
across
its
major
product
lines,
including
Westlaw
and
Practical
Law
on
the
legal
side
and
Checkpoint
on
the
tax
side,
as
well
as
Microsoft
365.
It
draws
on
a
multi-model
AI
architecture
—
working
with
frontier
models
from
Anthropic,
OpenAI
and
Google,
alongside
TR’s
own
proprietary
AI
technology
—
and
produces
structured,
citation-backed
outputs
rather
than
freestanding
text
generation.
On
data
privacy,
TR
has
stressed
that
customer
inputs
are
never
used
to
train
third-party
models
or
generate
outputs
for
other
users.
“One
million
professionals
have
chosen
CoCounsel,”
David
Wong,
TR’s
chief
product
officer,
wrote
in
a
related
blog
post.
“Not
for
pilots.
Not
for
experiments.
As
core
infrastructure
for
how
they
work.”
The
Road
to
a
Million
CoCounsel’s
path
from
launch
to
a
million
users
involved
considerable
iteration.
In
a
separate
blog
post,
Joel
Hron,
chief
technology
officer
at
TR,
described
the
early
months
after
Thomson
Reuters
introduced
AI
Assisted
Research
—
the
first
generative
AI
feature
in
Westlaw
—
as
challenging
and
formative.
“What
felt
strong
in
our
research
loops
needed
refinement
when
put
to
the
test
with
real
human
feedback,”
Hron
wrote.
Over
time,
he
acknowledged,
an
intense
focus
on
accuracy
created
its
own
trade-off,
in
that
the
system
became
highly
reliable
but
less
fluid.
“We
optimized
for
never
being
wrong.
Our
users
wanted
us
to
also
optimize
for
being
genuinely
helpful.”
That
tension,
Hron
wrote,
drove
CoCounsel’s
evolution
into
something
more
ambitious
—
including
the
development
of
Westlaw
Deep
Research,
which
the
company
describes
as
the
most
advanced
AI-powered
legal
research
system
available,
capable
of
analyzing
thousands
of
documents,
synthesizing
findings
across
jurisdictions,
and
delivering
court-ready
analysis
with
citations
and
reasoning.
What
Comes
Next
TR
used
the
million-user
announcement
to
tease
what
it
said
will
be
the
next
generation
of
CoCounsel
Legal,
which
is
entering
beta
soon.
The
new
version
is
designed
around
conversational
task
execution
—
allowing
a
lawyer
or
legal
professional
to
describe
an
objective
much
as
they
would
brief
a
colleague,
and
then
have
CoCounsel
build
a
plan,
retrieve
authoritative
sources
from
Westlaw
and
Practical
Law,
search
relevant
documents
and
precedent,
verify
citations,
and
deliver
structured
work
product
within
a
single
system.
Additional
next-generation
capabilities
within
CoCounsel
Tax
and
ONESOURCE+
are
planned
for
later
in
2026.
The
company
has
also
disclosed
it
is
developing
a
proprietary
large
language
model
designed
specifically
for
legal,
tax
and
compliance
use
cases
—
a
move
that
would
reduce
dependence
on
external
model
providers
for
its
most
sensitive
professional
applications.
Hron,
in
his
blog
post,
acknowledged
the
ambition
of
what
lies
ahead
while
expressing
confidence
in
the
team
that
got
CoCounsel
to
this
point.
“One
million
users
proves
we
are
trusted.
What
we’ll
prove
when
we
10x
that
number
this
year
is
that
we’ve
built
the
AI
professionals
genuinely
can’t
live
without.”
Thomson
Reuters
invested
more
than
$200
million
annually
in
productized
AI,
the
company
has
said,
and
has
indicated
it
has
approximately
$11
billion
in
capital
capacity
through
2028
for
continued
investment
and
acquisitions.