Lines are contracted at time 0, giving the borrower the option to draw on the line at time 1 or at
time
a
at an interest rate equal to a fixed contractual spread
s
over the reference rate. We analyze
cases in which the reference rate is either a credit-sensitive rate like LIBOR or a risk-free rate
r
like
SOFR. Purely for notational simplicity, given the increased model complexity, we assume that the
risk-free rate
r
is always zero. The reference rate is
R
1
for loans taken at time 1 and maturing at time
a
, and
R
a
for loans taken at time
a
and maturing at time 2. We ignore risk aversion throughout. For
the case of credit-sensitive reference rates, we take
R
1
and
R
a
to be positively correlated with the
unsecured borrowing rates of the bank, r + S
1
at time 1 and r + S
a
at time a.
The borrower will be blocked from drawing at time
a
if
S
a
≥
ˆ
S
, for some threshold
ˆ
S
. Because we
are conducting a marginal analysis, we take
ˆ
S
as given, although it may depend on the borrower
type. The spreads
S
1
and
S
a
are affiliated, so the conditional probability at time 1 that the borrower is
blocked from drawing at time
a
is increasing in
S
1
. The borrower will endogenously choose whether
to deposit any funds drawn at time 1. Any drawn funds outstanding at time
a
are for uses by the
borrower at that time, and are not left on deposit. If the borrower does not need cash at time a, any
previously drawn funds are repaid.
At time 0, the bank offers the borrower a menu
{(L
,
s) : L ≥
0
}
of credit line terms distinguished
by the size
L
of the line and the associated fixed spread
s
over the variable loan benchmark rate
R
.
At time 1, information reveals the credit spread
S
1
of the bank for unsecured wholesale funding
maturing at time
a
. Likewise, at time
a
, the credit spread
S
a
of the bank for loans maturing at time 2
is observed. Information is symmetric throughout.
The borrower will use the drawn funds only at time
a
, if at all. At time
a
, the benefit to the
borrower of having access to
x
in cash is
b(x
,
ψ)
, where
ψ
is a liquidity-preference variable that is
revealed at time 1 and
b
is a function with the same properties assumed in the basic model. At time 1,
given the committed size
L
of the credit line, the borrower chooses the amounts
q
1
to borrow at time
1. At time
a
, the borrower chooses the incremental amount
q
a
to borrow, if not blocked by the bank,
so as to maximize the benefit of access to the cash, net of the present value of the loan repayment. We
allow
q
a
to be negative, subject to
q
1
+ q
a
≥
0, with the idea that by time
a
, the borrower will either
have used the drawn funds or paid back funds drawn at time 1. At time 2, the total assets and total
liabilities of the bank are revealed and the bank is either solvent or not. For simplicity, the bank will
not default before time
a
, for example because the bank has no liabilities maturing before time 2. If
solvent at time 2, the bank pays back
q
1
(
1
+ S
1
)(
1
+ S
a
) + q
a
(
1
+ S
a
)
. The corporate borrower repays
the outstanding loan amount,
q
1
+ q
a
, whether or not the bank is solvent at time 2. The proportional
reputational or convenience cost to the borrower of not leaving the drawn funds on deposit at the
same bank is
e
. For simplicity, we assume that the borrower will not default on the credit line and
take
R
1
= r + S
1
. We don’t take
R
a
= r + S
a
, because we want to allow for the risk that the bank will
become much worse at time
a
than “LIBOR quality,” which as a result could prevent the borrower
from drawing or even make the bank unable to fund the draw request.
State by state, the borrower thus solves
V(L) = sup
0 ≤ q
1
+q
a
≤ L, W
E
[
b(Q + q
a
, ψ) − Wq
1
e − Q(1 + R
1
+ s)( 1 + R
a
+ s) − q
a
(1 + R
a
+ s) | S
1
, ψ
]
,
(15)
where q
a
is constrained to be non-positive on the event {S
a
≥
ˆ
S}, where
Q = q
1
(H + (1 − H)W),
and where
H
is the indicator of the event that the bank honors its deposit obligation at time
a
. We
take
P(H | S
1
)
to be a simple given function, for example linear, assuming that
S
1
has a sufficiently
bounded range. Or, for another example, we can take
H =
1
{S
a
<S
∗
}
, where
S
∗
is a threshold above
ˆ
S
.
54