In a
transaction,
something
is exchanged for
something else.
To this,
we can add
the concept of time.
This splits
the concept of transaction
in two:
In a
barter transaction,
something
(in the present)
is exchanged for
something else
(also in the present).
In an
investment transaction,
something
(in the present)
is
exchanged
for
something else
(in the future).
Note that,
by adding
the concept of
time,
we also add
the concept of
risk.
(The present is certain – but the future is uncertain.)