Discussion Paper No. 1044

ON THE CASH-FLOW
AND CONTROL RIGHTSOF CONTINGENT CAPITAL

Chris Mitchell

November 2018

The Institute of Social and Economic Research
Osaka University
6-1 Mihogaoka, Ibaraki, Osaka 567-0047, JapanOn the Cash-Flow and Control Rights of Contingent Capital
Chris Mitchell∗
November 5, 2018

Abstract
This paper develops a model of banking to study the risk-taking consequences ofcontingent capital (CC). It begins with the observation that partial conversion of CC
provides its owners with a portfolio of equity and debt. Since the former (latter) asset
typically induces a preference for risk taking (safety), the net preference of CC-holders
upon conversion should depend on their relative holdings of each asset, which in turn,depends on the amount of CC converted. In addition to acquiring cash-flow rights,
these conversions provide CC-holders with equity control rights, which afford themgreater influence over management’s portfolio selection. The paper demonstrates thatrational shareholders - that anticipate these endogenous preferences and equity control
rights - may be inclined to either: (1) dilute their own equity stakes through “excessive”
risk taking in order to create risk-loving and influential CC-holders; or (2) rule-out
conversion altogether through “excessive” safety, thereby preempting the creation of
influential and safety-loving CC-holders. The results also suggest that higher CC-toequity ratios can reduce the likelihood of reaching an “excessive” risk-taking equilibria.

Keywords: Contingent Capital, Corporate Governance, Bank Regulation, Blockholders,Shareholder Activism, Portfolio Choice.
JEL classification: G21, G28, G11, G34.

∗
Institute of Social and Economic Research, Osaka University, 6-1, Mihogaoka, Ibaraki, Osaka 567-0047,
Japan. Phone: +81-6-6879-8566. E-mail: mitchell@iser.osaka-u.ac.jp. I would like to acknowledge financial
support from JSPS KAKENHI Grant-in-Aid Number 15H05728.

1

1

Introduction

For better or worse, capital-adequacy ratios have become the centerpiece of banking regulation. Proponents of these argue that bank capital reduces ex-ante risk taking in addition
to bolstering loss-absorbing equity buffers. However, capital ratios also constrain lending
during times of financial stress when equity is both depleted and expensive. A security withthe potential to mitigate this problem can be found in Flannery (2005), which proposes theissuance of subordinated debentures that automatically convert into common equity whenrecapitalization is needed. These securities are generally referred to as contingent capital/convertibles (CC), and have been issued by a number of European banks.1 This paper
analyzes the effects of CC cash-flow and control rights on bank risk taking. Specifically, it
begins with the observation that partial conversion of CC provides its owners with a portfolio of equity and debt. Since the former asset is likely to induce a preference for risk taking,while the latter asset is likely to induce one for safety, the net preference of CC-holders upon
conversion should depend on their relative holdings of each asset, which in turn, depends
on the amount of CC converted. In addition to acquiring cash-flow rights, CC investors
also receive equity control rights, which afford them greater influence over management’s
portfolio selection. Anticipating these endogenous preferences and control rights, initialshareholders may find it optimal to dilute their own equity stakes through “excessive” risktaking in order to engender risk-loving and influential CC-holders. Conversely they may
find it optimal to rule-out conversion altogether through “excessive” safety, thereby eliminating the influence of safety-loving CC-holders. This paper develops a model of banking
to study the implications of these endogenous preferences and CC-holder control rights.
Prior to the 1980’s, US regulators refrained from imposing strict minimum capital requirements on banks, preferring instead to use judgment-based regulation tailored to specificinstitutions.2 However, in response to rapidly-diminishing capital levels at US banks during
the 1970’s and early 1980’s, the federal banking agencies introduced explicit minimum capital requirements in 1981. And by 1985, the Federal Reserve, the Office of the Comptrollerof the Currency, and the Federal Deposit Insurance Corporation agreed to harmonize theserequirements at 5.5% of adjusted total bank assets.3
However, US regulators were soon concerned that these 1985 requirements failed to adequately account for asset risk and off-balance sheet exposures, and desired to have uniform
international regulation (to level the playing field). This led central bank governors of the
G-10 countries to adopt the first Basel Accord (Basel I - fully implemented in 1993), which
introduced an 8% capital requirement. In spite of appreciably higher capital levels among
US banks around the implementation of Basel I (see Flannery and Rangan (2008) - which,incidentally, casts doubt on the effectiveness of Basel I for this trend) commentators cited
a number of its shortcomings, and work began on Basel II, which added a capital charge
for market and operational risk, and further disaggregated asset risk-weights. However,the 2007-2009 financial crisis hit before Basel II was fully implemented, and the subsequent analysis of this crisis exposed a number of Basel II’s limitations. As a result, work
began on Basel III, which increased the minimum capital requirement to 10.5%, added1

See Berg and Kaserer (2015) for a list of issuing banks, and Fiordelisi et al. (2018) for a list by country.
For brief histories of US capital regulation see Alfriend (1988) and Burhouse et al. (2003).
3
France, the UK and Germany, had risk-based capital standards in place by 1979, 1980 and 1985,
respectively.
22

a counter-cyclical capital buffer (at the discretion of national regulators, up to 2.5%) andincludes a simple leverage ratio (Tier 1 capital greater than 3% of non-risk-weighted assets).
The principle rationale for capital regulation has two components. First, equity and subordinated debt provide insulation against asset losses to senior creditors and deposit insurers.
Second, and more controversially, higher capital levels are purported to incentivise lower
ex-ante risk taking (for a recent dissenting view see Kashyap et al. 2008). This is typicallyrationalized by appealing to greater skin-in-the-game, as in Furlong and Keeley (1989),
Keeley and Furlong (1990), Hellmann et al. (2000), Cooper and Ross (2002) and Repullo(2004), the ability of capital risk-weights to discourage banks from selecting inefficient andhigh-risk portfolios, as in Kim and Santomero (1988), discouraging high-risk firms fromseeking bank charters by limiting their scalability, as in Morrison and White (2004), andreducing the probability that banks become undercapitalized and motivated to gamble forresurrection, as in Calem and Rob (1999).
Notwithstanding capital regulation’s potential effectiveness as a microprudential tool, it
has mixed effects on lending efficiency. On the one hand, higher capital levels facilitate efficient lending through a “balance sheet” channel, whereby well-capitalized banks face lower
wholesale-funding costs (Bernanke and Gertler 1995). While on the other hand, negative
capital shocks that result in binding capital constraints often encourage banks to reduce
lending, as opposed to raising additional equity, which is especially costly during times offinancial stress due to intensified debt overhang (Myers 1977) and heightened informational
asymmetries regarding bank value (Myers and Majluf 1984). Bernanke and Lown (1991)
appears to be the first study to empirically test for this “capital crunch” effect, which isfound using early 1990s US data. Peek and Rosengren (1997), and Watanabe (2007), corroborate this result using Japanese bank data, while also addressing the endogeneity ofbank capital w.r.t. loan demand. Brinkmann and Horvitz (1995) address the endogeneity
problem using US data, and also find evidence for a capital crunch, as does Gambacortaand Mistrulli (2004) using Italian data.4
Given the primary importance of bank lending for economic activity (see Gorton and Winton
2002, among many others, for a discussion), policy tools that reduce lending disruptions during times of depleted bank capital are certainly needed. One such tool is found in Flannery(2005), which proposes the issuance of “reverse convertible debentures” that automaticallyconvert into common equity when a bank’s capital ratio falls below a pre-specified level.
This prompt recapitalization not only staves-off costly bankruptcy, but may also reduce thefrequency and intensity of capital crunches. Support for this general idea is forthcoming
among a number of academics, policymakers and market participants. However, disagreement remains concerning the security’s primary design features: the conversion trigger, therate at which CC converts into equity, and the reference value of equity used for conversion.
In his original paper, Flannery recommended a market-value trigger, and a one-to-one conversion ratio of CC into common equity (both at current market prices). Market-value
triggers are also recommended by McDonald (2013), Calomiris and Herring (2013) and
Flannery (2016), and benefit from lower susceptibility to accounting manipulation, and are4

Most of the empirical evidence appears to be consistent with the capital-crunch hypothesis, however,all but one of Berger and Udell (1994)’s empirical tests are inconsistent with it.

3

forward-looking measures of capital value.5 The primary alternative is using equity’s bookvalue, as recommended by the Squam Lake Group (2009) and Pitt et al. (2011). This
trigger benefits from its insensitivity to market manipulation, its applicability to privatebanks, and the avoidance of multiple/no equilibria, as pointed out by Sundaresan andWang (2015). The model developed herein considers a book-value trigger, although it canalso accommodate market-value triggers. With respect to the rate at which CC converts
into equity, McDonald (2013) recommends a conversion ratio that benefit shareholders; thisis meant to reduce market manipulation by short-sellers (also discussed in Flannery (2016)
and Pennacchi (2010)). Berg and Kaserer (2015) report that most European issuances havethis feature.6 Taking the opposite view is Calomiris and Herring (2013) and D’Souza etal. (2009), who argue that conversion terms should benefit CC holders, as this will incentivise preemptive equity injections when capital levels become depleted. In the middle lies
Sundaresan and Wang (2015), which recommends no wealth-transfer upon conversion. The
current model accommodates all three possibilities. Finally, with respect to the reference
value of equity used for conversion, Calomiris and Herring (2013) and Flannery (2016)
recommend using equity’s contemporaneous market value, which ensures that the valueof converted-equity is proportional to the value of written-off CC, while McDonald (2013)
recommends using fixed reference values (specifically, conversion into a fixed number ofsharers), as does the Squam Lake Group (2009). Fixed reference values can reduce thechance of market manipulation by bondholders, who would otherwise have an incentive todepress stock prices in an attempt to acquire larger percentages of bank equity upon conversion. The current model accommodates both fixed- and market-based reference values,and can be described as follows.
Banks in the model are financed with equity, deposits and CC. Each bank holds an asset portfolio, whose risk can be adjusted in each period by way of a mean-preserving
spread/contraction.7 In addition to changing the bank’s payoff structure, these meanpreserving spreads/contractions affect its regulatory-capital requirement by adjusting its
asset-risk weights: larger spreads (contractions) make portfolios riskier (safer), and therefore, increase (decrease) the bank’s capital requirement. As considered by Glassermann andNouri (2012) and Flannery (2005, 2016), when banks in the model trigger a capital-ratio
violation, just enough CC is written-down to regain compliance. In this way, risk shifting
also affects the proportion of bank equity and debt held by CC-investors upon conversion.
A number of papers, including Koziol and Lawrenz (2012) and Pennacchi et al. (2014),
have argued that shareholders may be wary off CC due to their potential loss of control
upon conversion.8 One implications of this, as discussed in Berg and Kaserer (2015), is5

McDonald (2013) also recommends a “dual price” trigger: conversion occurs if and only if a bank’s stock
price and a pre-specified financial index fall below certain levels. This permits bankruptcy during “regular”
times, while it provides support for troubled banks during times of systematic stress.
6
Many have principle write-down clauses. This is necessary for private banks, as noted in Flannery(2014).
7
Rothschild and Stiglitz (1970) demonstrates that many notions of “riskiness” are encompassed bymean-preserving spreads.
8
Control issues may be particularly acute for CC owing to: (1) high ownership-dispersion among banking
institutions (Holderness (2003) provides references for the relevant evidence), which may be attributed tobank regulation substituting for large-shareholder monitoring, while simultaneously reducing the private
benefits of control; and/or (2) the class of investor that is likely to purchase CC en masse, which may consistof activist investors such as hedge funds, due to the potential ownership-restrictions placed on traditional4

that risk-averse CC-holders may shut down high-risk business lines upon gaining control
of a bank, thus reducing the market value of equity. The current paper agrees with thisconjecture, but only for certain cases. As noted above, partial conversion of CC leaves
its owners with a portfolio of bank equity and debt, and due to equity’s (debt’s) convex(concave) payoff structure, its value is an increasing (decreasing) function of asset-risk.
What separates this paper from the previous literature is that CC-holder risk-preferences
are determined endogenously, as part-and-parcel to their rational objective of wealth maximization, which involves maximizing the total value of their portfolio of bank debt andequity. In this way, CC-holders remain risk-averse when CC write-downs and equity transfers are relatively small, but become risk-loving when write-downs and equity transfers arelarge. This dichotomy is important, because as noted above, CC-holder preferences canmanifest themselves in further mean-preserving spreads/contractions via activism, with theassociated implications for bank value and financial stability. Furthermore, given that initialshareholders will anticipate these endogenous preferences, and can partially affect them via
risk shifting pre-conversion, the bank’s level of pre-conversion risk taking is also affected.
Taken together, the model has two distinct equilibria. In the first, shareholders engage in“excessive” risk taking, which increases the value of equity and creates an influential andrisk-seeking voting block that supports further risk-taking initiatives. In the second, shareholders engage in “excessive” safety, to avoid conversion altogether in an effort to preventthe creation of influential and risk-averse voting blocks.
The model’s two equilibria have diametrically-opposed implications for risk taking, andtherefore, studying which factors promote each - both bank-specific and regulatory - is warranted. Toward this end, the model is solved analytically, and a number of comparative
statics are run. This exercise recommends that CC-to-equity ratios ought to be relatively
high. For reasons explained below, the “excessive” risk-taking equilibria only materialize
when CC-holders are expected to become risk-loving post-conversion. When outstanding
CC is large (small) this requires a relatively large (small) write-down and equity transfer,which dilutes initial shareholders greatly (minimally) when CC-to-equity ratios are high(low); as a result, initial shareholders are more likely to select the “excessive” safety (risktaking) equilibria. The comparative statics also suggest that high debt-to-equity ratios
increase the likelihood of excessive risk taking, via more lucrative asset substitution (as inJensen and Meckling 1973). Finally, the rate at which CC converts into equity, and thebank’s risk-adjusted capital requirement, are shown to have mixed effects on bank risk taking.
In addition to providing an analytic solution, the paper also presents a set of numericalresults based on reasonable parameter values. These provide an indication of each equilibrium’s feasibility, while also helping to illustrate how the model’s variables interact with
one another.
This study is related to a growing literature on the risk-taking incentives created by CC; forrecent surveys of the CC literature see Calomiris and Herring (2013) and Flannery (2014).
Glasserman and Nouri (2012), for instance, demonstrates that non-monotonic relationships
may arise between asset volatilities and CC yields (initially decreasing - due to equity’s
greater upside potential - and then increasing), implying that banks can lower their funding
holders of conventional bank debt (both regulatory and self-imposed, see Pitt et al. 2011).

5

costs by adjusting asset risk - either down or up. The results of Koziol and Lawrenz (2012)
go further, suggesting that a substitution of CC for straight debt will always incentivize
greater risk taking on the part of banks, by lowering the expected cost of bankruptcy, while
maintaining the interest-tax shield of subordinated debt.9 Hilscher and Raviv (2014), Bergand Kaserer (2015) and Himmelberg and Tsyplakov (2015) consider the conversion terms ofCC, and how these will affect risk taking: banks in all three models attempt to force conversion when terms are favorable to shareholders by increasing asset volatilities or “burning”
money, in the first two papers, and the last paper, respectively. Pennacchi et al. (2014)
also suggests that favorable conversion terms will result in higher asset volatilities, and recommends a solution: issue CC with unfavorable conversion terms and provide shareholders
with the option to repurchase converted equity at CC’s par value. The current paper differsfrom these studies in a number of important ways. First, it considers multi-period risk
shifting by analyzing a bank’s optimal portfolio selection both before and after conversion.
Second, it explicitly models the risk-preferences of CC-holders, and thereby challenges thetendency to assume that these preferences run counter to those of initial shareholders.10
Third, it considers the effects of corporate-control changes on a bank’s portfolio selection,and illustrates that initial shareholders may prefer to relinquish control as opposed to selecting overly-conservative investment strategies.
This paper is also related to the literature on blockholder preferences and corporate control;
for a recent survey of the blockholder literature see Edmans and Holderness (2017). Twoparticularly-relevant studies are Dewatripont and Tirole (1994) and Dhillon and Rossetto(2014). The first demonstrates that optimal managerial contracts can be implemented when
corporate control is given to investors with the “correct” proportion of a firm’s debt andequity, and therefore, have the “correct” risk preferences. In Dhillon and Rossetto (2014), a
blockholder’s tolerance for risk is increasing in her level of portfolio diversification. As such,placing marginal control with well-diversified, and therefore risk-seeking investors (risk isefficient in this model), supports high firm value. Empirical support for the positive relationship between blockholder diversification and risk-seeking can be found in Facio et al.
(2001) for European firms.
The remainder of this paper is organized as follows. Section 2 describes the modelingenvironment. Section 3 presents the model’s general solution. Section 4 derives an analytic
solution to the model, and presents a number of comparative statics. Section 5 presents thepaper’s numerical results, and Section 6 concludes.

2

The Model

All investors in the model are assumed to be risk-neutral expected-wealth maximizes, andinterest rates are normalized to zero. Banks operate for two periods: 1 and 2. They enter
period 1 with a riskless asset portfolio that pays Xg at the end of period 2, and with deposit
liabilities and CC liabilities that promise to pay D and C at the end of period 2, respectively.
9

The future tax status of interest payments on CC is still uncertain.
Coffee (2011) argues that CC liabilities ought to be converted into preferred shares with substantial
voting rights, in order to create risk-averse blockholders. This argument likely presupposes that conversion
of CC into common equity may not necessarily produce these risk-averse blockholders. However, Coffee(2011) does not study the preferences of “conventional” CC-holders, nor does it comment on how these
preferences are likely to affect risk taking both before and after conversion.
10

6

Banks can adjust asset portfolios in each period by engaging in mean-preserving spreads
or mean-preserving contractions.11 To make matters simple, there are three possible payoffs at the end of period 2: Xg , Xb = Xg − ∆, and Xe = Xg + ∆, for some ∆ ∈ (0, Xg ].
Given this set of potential outcomes, mean-preserving spreads are equivalent to removing
probability mass from the central outcome (Xg ) and splitting it equally among the othertwo, whereas mean-preserving contractions are equivalent to removing equal amounts ofprobability mass from the extreme outcomes and adding it to the central one. It is assumed
that Xb < D + C < Xg , which implies that risky asset-portfolios entail risky debt. Banks
liquidate their assets at the end of period 2, pay outstanding debt obligations (to the extent
possible, with depositors receiving higher priority), and distribute anything that remains toshareholders.
In the absence of adjustment costs or constraints on risk shifting, shareholders would prefermaximum risk taking (see Rochet 1992),12 and seek to allocate half of the asset-portfolio’s
probability mass to the outcome Xb , and the other half to Xe , whereas creditors would
prefer maximum safety, and seek to allocate all of the portfolio’s probability mass to Xg(given that Xg > D +C). To address these extreme outcomes, it is assumed that controllingshareholders (whether they be initial shareholders or CC-holders, as discussed below) incur
private adjustment costs when engaging in mean-preserving spreads/contractions. Thesemay be thought of as time spent searching for new investments, or the mental cost ofrestructuring the workforce (e.g., firing staff that specialize in outgoing asset-classes). Denote these adjustment costs by the function λj A(θi ), where θi is the mass of probability
reallocated from the central outcome to the extreme outcomes (which may be negative) inperiod i, and λj ≥ 0 is a constant that may depend on the type of controlling shareholder(j = E for initial shareholders and j = C for CC-holders). It is assumed that A(0) = 0,
A(θ) = A(−θ) ∀ θ (i.e., adjustment costs are symmetric for mean-preserving spreads andcontractions), A0 (| · |) ≥ 0, A00 (| · |) ≥ 0 (where | | is the absolute-value operator, i.e., costs
are convex in the magnitude of risk shifting), and that costs are additive across periods.
Banks are subject to capital regulation at the beginning of each period, which createsa role for CC (beyond loss-absorbing subordinated debt). A chief purpose of CC is toquickly “recapitalize” banks that fail to meet their capital-adequacy ratios (CARs). Thisis accomplished by reducing the face value of CC liabilities, thereby increasing the bank’s
CAR. The amount by which CC is written down depends on the bank’s capital position prewrite-down and its capital requirement. Often, these requirements are increasing functionsof asset risk (e.g., Basel III). To accommodate this, it is assumed that capital regulationb + η(Θi ), where Rb ≥ 0 is the risk-free capitalis characterized by the function R(Θi ) = R
requirement, Θi is the aggregate mass of probability attributed to the extreme outcomes(i.e., not attributed to the outcome Xg ) at the beginning of each period i, and η(·) is the
additional capital requirement for Θi , where η(0) = 0 and η 0 (·) ≥ 0.13 It is assumed thatbanks satisfy their risk-free capital requirements at the beginning of period 1, which allows
us to focus on period 2 write-downs. Given the characterization of R(Θi ), and the factthat banks enter period 1 with a risk-free portfolio (i.e., Θi−1 = 0), the percentage of CC
11

These may be thought of as exchanging assets with identical market β’s and different idiosyncraticrisks.
12
Charter values typically moderate this type of excessive risk taking (see for example Keeley (1990) andHellmann et al. (2000)).
13
Portfolio risk is fully characterized by the variable Θi , and thus, no other information is pertinent.

7written-down in period 2, denoted by ω(·), must satisfy the following equality:
Xg − D − C(1 − ω(θ1 ))b + η(θ1 ),
=R
Xg

(1)

where the left-hand-side is the ratio of equity’s book value to the value of total assets (recall
that portfolios are mean-preserving spreads/contractions of one another, and therefore, havevaluations independent of θ1 - always equal to Xg ). Isolating ω(θ1 ) produces the CC writedown function:i
1 hb − η(θ1 )) .
D + C − Xg(1 − R(2)CFinally, to account for all mean-preserving spreads that fail to trigger CAR violations, andall mean-preserving spreads that require outside equity to satisfy the bank’s CAR, the following condition is imposed: ω(θ1 ) ∈ [0, 1].
ω(θ1 ) =Next we turn to the design features of CC. Unlike for standard debt contracts, the owners ofCC are compensated for write-down concessions in the form of equity grants. As discussed
in the introduction, the rate at which CC converts into equity, and the reference value ofequity used for conversion, are topics of academic debate, and vary in practice. For thecurrent analysis, it is assumed that CC converts into equity at the constant rate r ≥ 1.
This precludes the transfer wealth from CC-holders to initial shareholder via strategic conversion, and thereby streamlines the exposition.14 With regard to equity’s reference value,
two quantities are considered: 1) equity’s book value at the start of period 1; and 2) the
expected value of equity at the end of period 2 - after θ1 is selected and the expected valueof θ2 is also considered. The first of these is synonymous with using fixed reference values,
while the second is synonymous with using equity’s market value. Furthermore, since thefirst value permits an analytic solution, it is used for that purpose in Section 4, while bothreference-value assumptions are used for the numerical results of Section 5.15 Once the reference value of equity is selected, the percentage of shares transferred to CC-holders upon
conversion, denoted by π(·), must satisfy the following equation:π(θ1 ) =b − η(θ1 ))]r[D + C − Xg (1 − RrCω(θ1 )=.
E(θ1 , θ2 )E(θ1 , θ2 )(3)

where the reference value of equity (E(θ1 , θ2 )) may or may not depend on θ1 and θ2 , asdiscussed above.
The last substantive modeling issue concerns the bank’s corporate governance and control.
For simplicity, it is assumed that upon conversion, CC-holders use their newly-acquired
block of shares (and any existing influence they have as long-term creditors - see Nini etal. (2012) for a discussion of creditor-influence over management) to fully-influence management’s portfolio selection in period 2. Although extreme, this assumption allows us to14This assumption is not necessary for the paper’s main results, it merely streamlines the exposition.
For a treatment of strategic conversion that transfers wealth from CC-holders to shareholders, refer to theintroduction’s references.
15
As discussed in Section 5, equity’s reference value is of second-order importance for most of the numericalresults.

8

avoid the complicated and ad-hoc task of modeling relative influence among initial shareholders and new shareholders; a burgeoning research filed in its own right, but one thathas not yet produced a clear recommendation on how to model this interplay (see Holderness and Edmons 2017 for a discussion). The current paper’s concluding section offers astraight-forward refinement to this assumption, and discusses some of the complexities anduncertainties surrounding blockholder dynamics.
With the modeling environment now fully-characterized, we turn to its general solution
next.

3

The General Solution

This section characterizes the model’s general solution using a subgame-perfect Nash equilibrium. For simplicity, and without loss of generality, ∆ = Xg (i.e., Xb = 0 and Xe = 2Xg ).
Furthermore, the term “shareholders” is used to denote all shareholders on record at the
beginning of period 1. Given the model’s structure, it is solved backwards, starting withperiod-2 risk shifting.

3.1

Period 2

In period 2, the bank’s portfolio selection is either controlled by shareholders (when capitalrequirements are met) or by CC-holders (when CC is converted into equity). This brings
about two sets of nodes/cases at the beginning of period 2.
Case 1: When capital requirements are met, management selects the period-2 meanpreserving spread/contraction that maximizes expected shareholder wealth, net of adjustment costs, for a given θ1 . Thus, its problem is to:16(θ1 + θ2 )max : Xg − 1 −(D + C) − λE A(θ2 ),θ2
2
1− θ1 ],
2
where the lower-bound constraint on θ2 reflects the complete reversal of period-1 risk taking,while its upper-bound constraint is the highest level of risk taking available for a given θ1 .
The first order condition is:
S.t. θ2 ∈ [−θ1 ,−A0 (θ2 ) +

D+C
= 0,
2λE

which is independent of θ1 , and implies:0∗θ2,E= A −1



16

D+C
2λE


,

(4)

The intuition for this maximization-operand is as follows: maximizing the value of equity is equivalent
to maximizing the value of total assets minus the value of total liabilities. The former is always equal toXg (as discussed above), while the latter is equal to the face value of outstanding debt, multiplied by theprobability that debt is repaid in full (given that Xb = 0). This probability equals 1 − (θ1 + θ2 )/2, giventhat θ1 + θ2 of probability mass is subtracted from the central outcome, and of this, one-half is allocated tothe bad outcome Xb .

9∗∗where the E subscript on θ2,E
indicates shareholder control in period 2. The value θ2,E
is necessarily positive (and strictly so when A(·) is continuous), and equates the marginaltransfer of wealth from creditors to shareholders with the marginal adjustment cost. It is∗
assumed throughout that θ2,E
is sufficiently large to violate the bank’s capital requirement
if selected in period 1. If this were not the case, management’s intertemporal optimization∗ ), and CC never converts in equilibrium.
problem becomes trivial (θ1∗ = θ2∗ = θ2,E

Case 2: In the absence of equity ownership, CC-holders would rationally seek to maximize
the value of bank debt, net of personal adjustment costs, by selecting a weakly-negative
θ2 . However, arriving at case 2 implies that CC-holders have acquired equity states, and assuch, their true objective is to maximize the total value of their portfolio of bank securities.
Thus, management’s problem is to:(θ1 + θ2 )(D + C(1 − ω(θ1 )))max : π(θ1 ) Xg − 1 −θ22(θ1 + θ2 )+ 1−
C(1 − ω(θ1 )) − λC A(θ2 ), (5)21
S.t. θ2 ∈ −θ1 , − θ1 ,2
where the first component of this maximization-operand is the value of equity held by CCholders, the second is the value of outstanding CC, while the last is the adjustment cost.
The same constraints on θ2 ’s upper and lower bounds continue to apply. The first-ordercondition is:π(θ1 )(1 − π(θ1 ))D−
C(1 − ω(θ1 )) − λC A0 (θ2 ) = 0.
(6)
2
2
The first component of Equation 6 is the marginal wealth extracted from (transferred to)depositors by increasing (decreasing) asset risk, multiplied by the percentage of equity held
by CC-holders, the second component is the marginal reduction (increase) in the value ofCC from increasing (decreasing) asset risk, net of the CC-holders’ share of the resulting
increase (decrease) in equity value from reducing (increasing) the value of CC, whereas thethird component is the marginal adjustment cost.
The determining factor for whether CC-holders select a mean-preserving spread or contraction in period 2 is the sign of:(1 − π(θ1 ))π(θ1 )
D−
C (1 − ω(θ1 )) ,(7)
2
2i.e., the marginal net value of increasing asset risk from the perspective of CC-holders,conditional on θ1 . N V (θ1 ) is increasing in both ω(θ1 ) (the percentage of CC written down)and π(θ1 ) (the percentage of equity transferred to CC-holders), which are, in turn, increasing
functions of θ1 . When θ1 is sufficiently small, the reduction in CC-value from increasing
asset risk is greater in magnitude than the corresponding increase in converted-equity value,
N V (θ1 ) =10and thus, N V (θ1 ) < 0 ⇒ θ2∗ (θ1 ) < 0. Whereas when θ1 is sufficiently large, the opposite istrue, and N V (θ1 ) > 0 ⇒ θ2∗ (θ1 ) > 0. Therefore, solving for θ2∗ :
(1 − π(θ1 ))π(θ1 )0 −1∗D−
C(1 − ω(θ1 )) ,(8)
θ2,C = 1N V (θ1 ) A
2λC
2λC
∗
where the C subscript on θ2,C
indicates CC-holder control in period 2, and 1N V (θ1 ) is anindicator function characterized as follows:(−1 if N V (θ1 ) < 0
1N V (θ1 ) =1 if N V (θ1 ) ≥ 0.
∗
Unlike for the previous case, the level (and sign) of θ2,C
depends on the level of period-1
risk shifting through ω(θ1 ) and π(θ1 ).

3.1.1

Combining Cases 1 and 2 of Period 2

Taken together, the choice of θ1 produces three qualitatively-distinct sets of outcomes forperiod-2 risk shifting, as summarized in Figure 1. When θ1 is sufficiently small, shareholders
retain control of the bank’s portfolio selection in period 2, and management chooses the∗value of θ2 that maximizes expected shareholder wealth, net of adjustment costs (θ2,E
fromEquation 4). Second, when θ1 is relatively small, but large enough to trigger conversion, θ2∗
becomes negative, and reverses some, if not all, of the period-1 risk taking. Finally, when
θ1 is relatively large, θ2∗ becomes positive; further-increase the bank’s equity value. With
these results established, we move on to the bank’s period-1 problem next.
Figure 1. Control over Period-2 Portfolio Selection and the Sign of θ2∗
Shareholder
Control
∗
θ2,E
≥0
z
}|
{z

Creditor
Control
∗
θ2,C
<0
}|

low θ1

moderate θ10{zCreditor
Control
∗
θ2,C
>0
}|

{

high θ1

θ1This figure depicts the relationship between θ1 and: (1) which class of investor controls the bank’s portfolio
selection in period 2, and (2) the sign of θ2∗ . When θ1 is relatively small, banks adhere to their capital require∗ments and management selects θ2,E
from Equation 4. When banks fail to meet their capital requirements,
and the value of θ1 is relatively low, CC-holders seek to increase the value of outstanding debt, and thereby,
management selects a negative θ2 . Conversely, when θ1 is relatively large, CC-holders have relatively little
bank debt, and a relatively large amount of bank equity; this induces CC-holders to increase the value ofequity, and thereby, management selects a positive θ2 .

3.2

Period 1

Management’s problem in period 1 is to select the value of θ1 that maximizes expectedshareholder wealth, conditional on correctly anticipating the best-response function of CCholders and shareholders in period 2. This involves comparing two values: the maximum
11expected wealth of shareholders when they retain control (case 1), and their maximum
expected wealth when CC-holders gain control (case 2). As shown below, whenever the
first value exceeds the second, management optimally selects the largest period-1 meanpreserving spread that fails to trigger conversion, whereas whenever the second value islarger, management always selects a mean-preserving spread in period 1 that is sufficiently
large to induce additional risk taking on the part of CC-holders in period 2.
Case 1: Conditional on shareholders retaining control in period 2, management selects:
∗−1 Xg − (D + C)b ,
θ1,E = η−R
Xg∗∗
where the E subscript on θ1,E
indicates anticipated shareholder control in period 2. θ1,E
isthe maximum value of θ1 that fails to trigger conversion (see Equation 1). Its optimality∗
follows from the positive relationship between shareholder wealth and θ1 ∀ θ1 < θ2,E
(see∗
Equation 4), and the previous assumption that θ1 = θ2,E triggers conversion if selected inperiod 1.

Case 2: Conditional on CC-holders gaining control of the bank’s portfolio selection inperiod 2, management selects:∗
θ1,C= arg max :θ1∗ (θ )  θ1 + θ2,C
1
D + C(1 − ω(θ1 )) − λE A(θ1 ),1 − π(θ1 ) Xg − 1 −2∗ indicates anticipated CC-holder control in period 2. θ ∗ maxwhere the C subscript on θ1,C
1,C
∗ (θ ),
imizes the expected wealth of shareholders given the functions ω(θ1 ), π(θ1 ) and θ2,S
1
∗ (θ ∗ ) > 0 is a necessary condition for managederived above. As shown in Appendix A, θ2,C
1,C
∗ in equilibrium. That is, whenever management selects a mean-preserving
ment to select θ1,C
spread that triggers conversion, the resulting ω(θ1 ) and π(θ1 ) must be sufficiently large that
CC-holders become risk-loving, and prefer additional risk taking in period 2. This corresponds to the right-most region of Figure 1.
∗ (θ ∗ ) > 0 is a necessary condition for conversion, all outcomes involving
Given that θ2,C
1,C∗
∗ (θ ) < 0 can be ruled-out (the middle region of
θ1 > θ1,E(conversion is triggered) and θ2,C
1
Figure 1). This allows us to focus on the left- and right-most regions of this figure whensearching for an equilibrium.

3.3

Equilibrium

Finally, to determine the equilibrium values of θ1 and θ2 , management compares the ex∗ , θ ∗ } (Case 1) to that under action
pected wealth of shareholders under action set {θ1,E
2,E∗ , θ ∗ } (Case 2), and selects whichever one produces the highest value.17
set {θ1,C
2,C
To understand the tradeoffs that shareholders face in period 1, it is instructive to separate
the difference in expected shareholder wealth from implementing the first and second ac∗ , θ ∗ } minus wealth under {θ ∗ , θ ∗ }) into the following 5tion sets (wealth under {θ1,E
2,E
1,C 2,C
components (with descriptions below):17∗∗
For brevity, θ2,C(·)’s argument is omitted here, and below, when it is evaluated at θ1,C
.

12

2.
1.
}|
{
z
}|
{








∗
∗
θ∗ +θ∗∗ ) X − 1 − θ1,C +θ2,C∗ )∗ )π(θ1,C
D + C 1 − ω(θ1,C− 1 − 1,C 2 2,C Cω(θ1,C
g
2
z

(9)


∗ ) − λ A(θ ∗ )+ λE A(θ1,C
E
1,E

|

{z
3.



∗ ) ±
− λE A(θ2,E}| {z }4.

∗θ∗ −θ∗
1,E −θ1,C+ 2,E 2 2,C
2

 θ∗

|

{z
5.



(D + C)}

Description of Each Component:
1. The value of equity transferred from shareholders to CC-holders. This
component is necessarily positive: no equity is transferred when capital requirements
are satisfied.
2. The reduced face value of CC. This component is necessarily negative: no CC
is written-off when capital requirements are satisfied.
3. The period-1 adjustment-cost differential. This component is necessarily posi∗∗
tive: greater period-1 risk shifting entails a higher adjustment cost, and θ1,C
> θ1,E
from above.
4. The period-2 adjustment-cost differential. This component is necessarily negative: adjustment costs are only incurred by controlling shareholders, and original
shareholders only retain control of the bank’s portfolio selection under the first actionset.
5. The differential in total wealth extracted from creditors. This component
may be positive or negative, depending on the relative magnitude of aggregate risk
∗ + θ ∗ ) vs. (θ ∗ + θ ∗ ).
shifting arising from each action set, i.e., (θ1,E
2,E
1,C
2,C
∗ , θ ∗ } (shareholder control)
Shareholders will unambiguously recommend action set {θ1,E
2,E∗ , θ ∗ } (i.e., a negative
when the bank’s total risk taking is lower under action set {θ1,C
2,Cth
5 component). In this case, both the total value of equity, and the percentage of equity
held by shareholders, is lower. Conversely, if aggregate risk taking under CC-holder control
is higher (i.e., a positive 5th component), shareholders face a legitimate tradeoff between
owning 100% of a bank with relatively low equity value, and owning less than 100% of abank with relatively high equity value. As discussed below, Components 1 (equity dilution)and 5 (wealth extracted from creditors) are the most important factors for determining θ1∗ .

4Analytic Solution and Comparative Statics

This section derives an analytic solution to the bank’s problem in order to evaluate theeffect that each parameter has on the bank’s propensity to adjust portfolio risk in periods
1 and 2. To simplify the exposition, the following 7 assumptions are made. However, they
are either made without loss of generality, or are justifiable based on empirical grounds.
13

1. Unit expected profit: Xg = 1.
b + ηbθ1 (b2. Affine capital requirement: R(θ1 ) = R
η relatively small).
b = E1 = 1 − D − C (where E1 is period 1 book
3. No excess capital in period 1: R
18
equity).
4. Banks are primarily deposit-funded: D >> C + E1 .
5. There are two magnitudes of risk shifting available in each period i (in addition tob ±2θ},
b i = 1, 2.19
the null option of zero): θi ∈ {0, ±θ,
b = 0.
6. The lower level of risk shifting is costless: A(±θ)
bb = θ(D+C)
b A
b > 0, λE = λC = 1.
7. The higher level of risk shifting is costly: A(±2θ)
+ A,
2

4.1

Period 2

Following the process outlined in Section 2, the model is solved using backward induction,
starting with period-2 risk shifting for both cases.
Case 1: When shareholders retain control of the bank’s portfolio selection in period 2∗(i.e., θ1 = 0 from assumption 3) θ2,E
= θb from assumptions 5, 6 and 7. In this case, expectedshareholder wealth is:θb
E1 + (D + C).
2I.e., the initial value of equity plus the amount of wealth extracted from creditors in period 2.
Case 2: When CC-holders assume control of the bank’s portfolio selection in period 2b from assumption 3) the value of θ∗ (θ1 ) depends on the functions(i.e., θ1 equals θb or 2θ,2
ω(θ1 ) and π(θ1 ) from Equations 7 and 8. From assumptions 1, 2 and 3, and Equations 2
and 3, these simplify to:ω(θ1 ) =

ηb
θ1 ,
C

(2.1)

π(θ1 ) =

rb
η
θ1 .
E1

(3.1)

and

From these two equations, and Equation 7, the threshold value of θ1 for which CC-holders
are indifferent between increasing/decreasing portfolio risk solves:rbη
C − ηbθ1
θ1 (D + C − ηbθ1 ) =
,
2E1
2
18

This assumption is natural given that bank equity is typically more expensive than bank debt. This
cost-of-capital differential is often attributed to debt’s explicit/implicit government guarantee, its use asa medium-of-exchange, and its potential to improve corporate governance (see Kashyap et al. (2008) and
Admati et al. (2013) for both sides of this corporate-governance argument).
19
Subject to: θb ∈ (0, 1/2], θ1 ≥ 0, θ2 ≥ −θ1 and that unit probability mass is maintained.

14where the left-hand-side is the marginal benefit of increasing portfolio risk via a higher
equity value, and the right-hand-side is the marginal cost of increasing portfolio risk via
a lower CC value. Simplifying this expressing, and ignoring the higher-order term (i.e.,ηb2 θ2 ≈ 0), produces the following condition:∗
θ2,C(θ1 ) ≥ 0 iff C −ηbθ1 (r(D + C) + E1 ) ≤ 0,
E1

and the following threshold value of θ1 that produces indifference:
θ1T =

CE1
.
ηb [r(D + C) + E1 ](10)

When θ1 exceeds this value, CC-holders optimally increase risk-taking in period 2, whereas
whenever θ1 < θ1T , they decrease if. Taking the first derivative of Equation 10 with respect
to each parameter provides our first proposition and corollary:
Proposition 1 Under assumptions 1-7, and for a given level of period-1 risk taking, management is more likely to select a mean-preserving spread (i.e., increase portfolio risk) when
the initial value of equity and the original face value of CC are low, and when outstanding
deposits, the conversion ratio and the capital requirement are high. Whereas management
is more likely to select a mean-preserving contraction for the opposite.
Corollary 1 As the bank substitutes more of its conventional debt with CC, management
is more likely to select a mean-preserving contraction in period 2 (i.e., reduce portfolio risk)
since θ1T increases. (Again, under assumptions 1-7, and for a given level of period-1 risktaking).
The intuition for these results is as follows. More stringent capital regulation (i.e., a higher
ηb) induces larger CC write-downs and equity transfers for any level of period-1 risk taking, which simultaneously increases the marginal benefit of further risk taking (via higher
equity ownership by CC-holders) and reduces the marginal cost (by lowering outstanding
CC). Taken together, higher values of ηb increase the likelihood of period-2 risk taking. Furthermore, the initial book value of equity (E1 ), the amount of outstanding deposits (D)and the conversion rate (r), all affect the likelihood of period-2 risk taking via the marginal
benefit of increasing asset risk: specifically, a higher value of r, and a lower value of E1 ,both increase the percentage of equity transferred to CC-holders for any CC write-down,
while a higher value of D increases the rate at which wealth is extracted from depositors via
mean-preserving spreads. Conversely, the original face value of CC (C) operates throughthe marginal cost of increasing risk: higher values of C occasion larger values of outstanding
CC for any amount written off, and therefore, increase the marginal cost of risk taking.
This also explains Corollary 1.
Equation 10 is also useful for identifying the set of θb values that should be focused ongoing forward. Notice that when θb < θ1T /2, CC-holders always select a mean-preserving
contraction upon gaining control of the bank, whereas when θb > θ1T they always select amean-preserving spread. However, the interesting case is when θb ∈ (θ1T /2, θ1T ). In this situation, CC-holders optimally select a mean-preserving contraction when period-1 risk taking
15

is low (due to relatively small values of ω(θ1 ) and π(θ1 )) and select a mean-preserving
spread when period-1 risk taking is high (due to relatively large values of ω(θ1 ) and π(θ1 )).
Therefore, in what follows, it is assumed that θb ∈ (θ1T /2, θ1T ).
The final step of this subsection is to determine the level of risk shifting selected by CCholders upon gaining control in period 2. From assumptions 6 and 7, we can infer that∗b and θ∗ = θb when θ1 = 2θ.
b That is,
CC-holders optimally select θ2,C
= −θb when θ1 = θ,2,Cb due to the highCC-holders always avoid the two extreme risk-shifting options (i.e., ±2θ),
adjustment-cost of selecting them (see Appendix B for a proof of this).
The above results are summarized in Table 1, and together characterize the set of optimal
strategies at each period-2 decision-node/case. Notice that θ2∗ (θ1 )’s overall structure is similar to that presented in Figure 1.
Table 1. Optimal Strategies at Each Period-2 Decision Node: θ2∗ (θ1 )
θ1
0
θb
2θb

θ2∗ (θ1 )θb

Period-2 Control−θbθbCC-holders

Shareholders
CC-holders

This table reports the best-response of management at each period-2 decision node/case. The first column
specifies each possible decision node/case, the second reports the best-response at each of these nodes/cases,
while the third reports the investor-type in control of the bank’s portfolio selection.

4.2

Period 1

With the set of period-2 strategies now derived, we can solve for the bank’s optimal level of
period-1 risk shifting. Following the procedure outlined above, this involves comparing the
expected wealth of shareholders when they retain control of the bank’s portfolio selection,
to their maximum expected wealth when CC-holders gain control.
Case 1: From Section 3 we know that management always selects the highest θ1 that fails totrigger conversion whenever shareholder-control is optimal in period 2. Given Assumptions
3 and 5, this corresponds to θ1 = 0, which produces an expected shareholder wealth of:θb
W ealth(0) = E1 + (D + C),
2from above.
Case 2: We also know from Section 3 that management always selects a mean-preserving
spread that induces additional risk taking on the part of CC-holders whenever transferringb since θ∗ (θ)
b = −θb from Table 1. This
control in period 2 is optimal. This rules-out θ1 = θ,2,Cleaves θ1 = 2θb as the only candidate.20
20

To see this result more clearly, note that expected shareholder wealth when θ1 = θb is:16b ω(2θ)Cb = 2θbbη of CC is written-down from Equation 2.1, and the percentage
When θ1 = 2θ,b = 2θrbb η /E1 from Equation 3.1. Taken together,of equity transferred to CC-holders is π(2θ)
this results in an expected shareholder wealth of:
!
!


b 
b + C)
2rb
η
θ
3
θ(D
b = 1−bη
b ,W ealth(2θ)
E1 + θb D + C − 2θb
−
+A
E1
2
2
b is thewhere the first bracket is the percentage of equity retained by shareholders, 3θ/2bprobability of reaching the excellent state, D + C − 2θbη is the remaining face value of
aggregate debt in period 2, while the right-most bracket contains the adjustment cost of
selecting θ1 = 2θb in period 1.

4.3

Equilibrium

Finally, to determine the equilibrium values of θ1 and θ2 , management compares the exb (Case 1) to that under action set
pected wealth of shareholders under action set {0, θ}bbb and ignoring the higher-order{2θ, θ} (Case 2). Subtracting W ealth(0) from W ealth(2θ),
2321
terms (i.e., 3b
η θb /2 and 3rbη θb ) produces the following condition:
"
#
b
3rb
η θb2
θ
b + C) −b − 2rbη θb −
θ1∗ = 2θbiff
θ(D(D + C) + A(D + C) > 0.
2
E1
The first term of this condition’s right-hand-side captures the additional benefit of selectingb2θb in period 1: the probability of reaching the excellent state increases by θb (i.e., 3θ/2b
for Case 1 vs. θ/2 for Case 2). The bracketed term captures the direct adjustment costof selecting 2θb (from Assumption 7), while the last two terms capture the indirect costs:
2rbη θb of equity’s book value is transferred to CC-holders during the initial conversion, while3rbη θb2 (D + C)/E1 of equity’s capital gain accrues to CC-holders and not shareholders.
Taking the first derivative of this condition with respect to each parameter provides our
second proposition and corollary:
Proposition 2 Under assumptions 1-7, and given θb ∈ (θ1T /2, θ1T ), management is more
likely to select a high level of period-1 risk taking when outstanding deposits, the original
face value of CC and the initial value of equity are high, and when the conversion ratio, theb are low. Whereas management
capital requirement and the adjustment cost parameter (A)is more likely to forgo period-1 risk taking altogether for the opposite.
b =W ealth(θ)



rb
ηb
b
1−
θ E1 = E1 − rbη θ,E1b the bank fails to meet its period-1
which is strictly less than W ealth(0) from above. By selecting θ1 = θ,capital requirement, which brings about CC conversion, and dilutes shareholders. Furthermore, the low levelof period-1 risk shifting results in relatively small values of ω(θ1 ) and π(θ1 ), which induces CC-holders to
reduce asset risk in period 2 in an effort to increase the value of outstanding debt. This, in turn, fully-reverses
all period-1 risk shifting, which results in an aggregate equity value of E1 . Thus, by selecting θ1 = θb insteadof θ1 = 0, shareholders simultaneously reduce the total value of equity, and dilute their own equity stakes.
This is precisely the scenario that shareholders wish to avoid.
21
These terms are 1 and 2 orders of magnitude lower than the others, respectively, for reasonable parameter values.

17

Corollary 2 As the bank substitutes more of its conventional debt with CC, management
is more likely to forgo period-1 risk taking. (Again, under assumptions 1-7 and given θb ∈(θ1T /2, θ1T ))The results of Proposition 2 can be explained as follows. As leverage increases from anincrease in either D or C, the rate at which wealth is extracted from creditors, via meanpreserving spreads, increases. This makes risk taking more desirable on the margin. Conversely, as r and ηb increase, and as E1 decreases, a larger percentage of the bank is transferred to CC-holders upon conversion for a given capital-ratio violation; the resulting equity
dilution makes risk taking less desirable on the margin. Furthermore, risk taking is clearlyless desirable when adjustment costs are higher.
Corollary 2 follows from the fungibility of deposits and outstanding CC with respect tocreditor-wealth extraction via asset substitution,22 and that shareholders will only advocate
for CC conversion when equity dilution is sufficiently low (Component 1 of Expression 9).
This last requirement places an upper bound on θb (call this θbU ); see Appendix C for a proofof this. Furthermore, as the bank substitutes its conventional debt with CC, θ1T increases(from Corollary 1), which causes the set {θb | θb > θ1T /2 and θb < θ1T } to shift upwards. This
makes θb < θbU less likely to occur.

4.4

Discussionb or action set {2θ,b θ},bIn the preceding analysis, management either selects action set {0, θ}bbwith corresponding aggregate risk shifting of θ and 3θ, respectively. In the first case,management avoids period-2 conversion altogether in an effort to prevent the creation of influential and risk-averse blockholders; the type of blockholder championed by Coffee (2011).
In the second case, management selects a relatively high level of period-1 risk taking, toboth increase the value of equity, and to create an influential and risk-seeking voting blockthat supports management’s future risk-taking initiatives.
In order to reach the second equilibrium, two conditions must be satisfied. First, CC-holders
must find it optimal to select a mean-preserving spread in period 2, and second, shareholders must find it optimal to permit conversion. Both of these requirements are less likely
to be satisfied when banks substitute relatively large quantities of subordinated debt withCC - from Corollaries 1 and 2 - which recommends that CC-to-equity ratios ought to berelatively high.23
With respect to the second equilibrium’s existence, Propositions 1 and 2 indicate thatmost of the model’s parameters have a contradictory effect on the likelihood of satisfying
both conditions simultaneously, with the exception of outstanding deposits (D) (having ab (having a negative effect).
uniformly-positive effect) and the adjustment-cost parameter (A)For the other parameters, the two conditions are only satisfied when their values lie withina jointly-determined subset of the parameter space. Specifically, the first condition is only
22

That is, once θ1 is selected (and thus ω(θ1 ) and π(θ1 ) are determined), the market value of equity
increases at the same rate regardless of whether wealth is extracted from depositors or remaining CCholders via asset substitution. Thus, a higher amount of C - given a fixed total debt/equity ratio - leaves
b + C) unchanged.
the quantity θ(D23
To see this result numerically, compare the results of Section 5 to those of Appendix D.

18

satisfied when CC investors have a sufficiently large equity stake and/or hold a sufficiently
small amount of debt upon conversion. These requirements place upper bounds on E1 andC, and lower bounds on r and ηb. Conversely, the second condition requires that equity
dilution be relatively modest and/or that gains from risk taking be relatively high. These
requirements place lower bounds on E1 and C, and upper bounds on r and ηb.
Given these restrictions, a natural question that arises is whether the “excessive” risk taking
equilibria actually exist for reasonable parameter values. To provide an indication of this,
we turn to the numerical results next.

5

Numerical Results

This section presents a set of numerical results that illustrate the paper’s main theory: CCholders may petition the bank’s management to increase or decrease asset-risk dependingon their portfolio of bank debt and equity. Shareholders will respond to these endogenous
preferences by petitioning management to either select high or low (possibly zero) meanpreserving spreads in period 1. In accordance with the analytic solution derived above, theb ±2θ},
b i = 1, 2,
first set of numerical results is based on discrete risk shifting, i.e., θi ∈ {0, ±θ,24while the second set of results is based on continuous risk shifting.

5.1

Discrete Risk Shifting

As before, Xg is normalized to 1. It is assumed that deposits constitute the vast majorityof bank funding, and as such, D = .85. Of the remaining .15 in asset value, one-third is
allocated to contingent capital (C = .05), while two-thirds are allocated to equity’s bookb = .1. Furthervalue (E1 = .1).25 Banks have no excess capital in period 1, and thus, R
more, ηb is set equal to .1. Banks may select one of five risk-shifting levels in each period: 0;±.05; and ±.1, subject to maintaining a unit measure of probability. There is no personal
adjustment cost for θi = ±.05, while it is .025 for θi = ±.1.26 These parameter values arereported in Table 2.
The first set of numerical results are reported in Table 3. These were derived using bothreference-value assumptions: the results contained in column (1) correspond to the use of
equity’s book value, while those in column (2) correspond to the use of its market value.
Capital requirements are adhered to in both cases when θ1 = 0, and thus, no CC is written
down. Conversely, when θ1 = .05 (θ1 = .1) a capital shortfall of .005 (.01) arises, which
triggers a 10% (20%) CC write-down. These results are reported in rows (1) - (3) of Table 3. The reference value of equity under the first assumption (book value) is .1 regardless
24

To the extent possible using numerical methods.
As pointed out by Sundaresan and Wang (2015), it is difficult to calibrate the parameters of CC
properly using available bank data, as CC is not yet widely used by banks. However, assigning 15% of abank’s asset-value to its total capital (CC plus equity) is consistent with the estimates of Pennacchi et al.
(2014) for: Bank of America, Citygroup and JPMorgan Chase (12.4% of total capital on average: common
stock, preferred stock and subordinated debt). It is also consistent with Berg and Kaserer (2015), whichuses 85% for deposits, 5% for CC and 10% for equity, and similar to Glasserman and Nouri (2012) (equityof 10% and CC between 5%-15%), Flannery (2005, 2016), Sundaresan and Wang (2015) and Himmelberg
and Tsyplakov (2015) (all assuming equity of 8% and CC of 5%).
b26
b = .0025 to this value equals .025. See Assumption 7 from Section 4.
Note: θ(D+C) = .0225. Adding A
25

2

19

Table 2. Parameter Values for the Discrete Risk-Shifting Numerical Results
Parameter

Value

Parameter
θb

Value

Xg

1

D

.85

0

.05

b
A(±θ)
b
A(±2θ)

C

.025

b
E1 /R

.1

λE

1

ηb

.1

λC

1

.05

This table reports the base-case parameter values used for the discrete risk-shifting numerical results.

of θ1 . Therefore, π(.05) = 5% and π(.1) = 10% in this case, as reported in rows (4) - (6)of Table 3. Under the second assumption (market value), both the reference value of equity, and the percentage of equity transferred to CC-holders upon conversion, are solutions∗ (.05) = −.05 while
to a fixed-point problem. This problem is solved by noting that θ2,C∗
θ2,C (.1) = .05 for both reference value assumptions (see rows (7) - (9) of Table 3), due tothe relatively high (low) value of outstanding CC, and the relatively low (high) percentageof equity transferred to CC-holders, when θ1 = .05 (θ1 = .1). As a result, there is no aggregate risk shifting when θ1 = .05, and equity’s only bump in market value stems from thereduction in outstanding CC. In this case, the market value of equity is .105 (i.e., E1 plus
10% of C). With a market value of .105, π(.05) = 4.8% under the second reference-value
assumption, which is marginally lower than under the first. Conversely, there is a relatively∗ (θ ) = .15. This, in addition
large amount of risk shifting when θ1 = .1 since θ1 + θ2,C
1
to the relatively large reduction in outstanding debt (20% of C), results in a high market
value of equity, which equals .1768 in this case. Therefore, π(.1) = 5.7% under the second
reference-value assumption, which is 4.3% lower than under the first (see rows (4) - (6) of
Table 3 for the percentage of equity transferred upon conversion, and rows (10) - (12) forthe market value of equity).27
If management selects θ1 = 0, expected shareholder wealth becomes .1225 under bothreference-value assumptions, as all equity is retained, and .0225 of wealth is extracted from∗∗ (D + C)/2 = .0225). If management selects
creditors in period 2 - since θ2,E
= .05 (i.e., θ2,E
θ1 = .05, expected shareholder wealth becomes .0998 (.1) under the first (second) referencevalue assumption, since shareholders retain 95% (95.2%) of the bank’s equity in period 2,
which is only worth .105 in aggregate (i.e., E1 plus the 10% of C that was written down).
Finally, if management selects θ1 = .1, expected shareholder wealth becomes .1341 (.1418)
under the first (second) reference-value assumption, since shareholders own 90% (94.3%) of27
It should be noted that control changes do not imply that CC-holders have acquired a majority ofbank equity - see Berle and Means (1932) for an early analysis of the “working control” exerted by minority
interests of diffusely-held corporations - only that CC-holders have gained a sufficient level of influence
through their block of shares (the same point is made in Berg and Kaserer (2015), for instance). It is beyond
the scope of the current analysis to estimate the percentage of shares needed to gain this influence - which
depends on the particular bank in question, its corporate charter, its legal environment, the compositionof its original shareholders, etc. - and therefore, no attempt was made to calibrate the numerical results tospecific values of π(θ1 ). As such, all results pertaining to CC-holder influence and π(θ1 ) should be viewed
as qualitative in nature, and not quantitative.

20

Table 3. Numerical Results: Discrete Risk Shifting
(1)
Book
Value

(2)
Market
Value

(1)
(2)
(3)

ω(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

0
10
20

0
10
20

(4)
(5)
(6)

π(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

0
5
10

0
4.8
5.7

(7)
(8)
(9)

θ2∗ (θ1 )Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

.05
-.05
.05

.05
-.05
.05

(10)
(11)
(12)

Market Value of Equity
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

.1225
.1050
.1768

.1225
.1050
.1768

(13)
(14)
(15)

Expected Shareholder Wealth
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

.1225
.0998
.1341

.1225
.1000
.1418

This table reports the numerical results for the discrete risk-shifting case. Column (1) reports the set ofresults derived using a constant reference value (book value), while Column (2) reports the set of results
derived using equity’s market value. ω(θ1 )(%) is the percentage of CC written down, π(θ1 )(%) is thepercentage of equity transferred to CC-holders upon conversion, while θ2∗ (θ1 ) is the value of period-2 risk
shifting.

the bank’s equity in period 2, which is worth .1768 (i.e., E1 (.1), plus the 20% of C that
∗ (θ ))(D + C(1 − ω(θ ))/2 of wealth extracted fromis written down (.01), plus (θ1 + θ2,C
1
1
creditors in periods 1 and 2 (.0668)), and they need to pay an adjustment cost of .025 forselecting θ1 = .1. These results are reported in rows (4) - (15) of Table 3.
Given that expected shareholder wealth under action set {θ1,E , θ2,E } = {0, .05} is .1225 forboth reference-value assumptions, while it is .1341 (.1418) under action set {θ1,C , θ2,C } ={.1, .05} for the first (second) reference-value assumption, the “excessive” risk-taking equilibrium is reached in both cases, and aggregate risk taking is .15.
Appendix D contains an alternative, but plausible, set of parameter values (.05 of C issubstituted for D) that supports an “excessive” safety equilibrium.
21

5.2

Continuous Risk Shifting

The next set of numerical results are analogous with continuous risk shifting. These aremeant to provide a clearer picture of how the model’s variables interact with one another.
For this exercise, all parameter values remain unchanged from Section 5.1, except that personal adjustment costs are remodeled to accommodate continuous risk shifting. Toward∗ )λ . The
this end, it is assumed that A(θi ) = θi2 for i = 1, 2, λE = 2.9, and λC = π(θ1,CE
first assumption produces a simple, convex and symmetric cost function, the second generates a set of results that are quantitatively similar to the ones presented above, while thelast assumption accommodates a proportional adjustment cost (proportional to ownershipshare).
The first set of continuous risk-shifting numerical results are derived using equity’s market
value as its reference value, and are reported in Figure 2. Panel 1 of this figure plots thebank’s capital requirement as a function of period 1 risk shifting (left axis). Banks satisfy
these requirements with initial book equity when θ1 = 0. In this case, shareholders retain
control of the bank’s portfolio selection in period 2, and management selects the value ofθ2 that maximizes expected shareholder wealth. This is plotted in Panel 2 as a function of∗= .078 (see row (7) ofθ2 . In this case, expected shareholder wealth is maximized at θ2,E
Table 4).
When θ1 > 1, banks fail to satisfy their capital requirements at the beginning of period
2, and some CC is written down; the amount by which this happens is plotted in Panel 1(right axis). As before, the percentage of equity transferred to CC-holders upon conversion, and the period-2 mean-preserving spread/contraction, are solutions to a fixed-point
problem involving equity’s market value. After solving this problem for each grid-point of∗ (θ ). These are plotted in Panels 3 and 4,
θ1 > 0, we obtain the graphs of π(θ1 ) and θ2,C
1
respectively.28 For all values of θ1 < .067, CC-holders select a mean-preserving contraction∗ (θ ) - due to the relatively low values
in period 2 - as indicated by negative values of θ2,C
1of ω(θ1 ) and π(θ1 ). Conversely, CC-holders select a mean-preserving spread when θ1 ≥ .067.
∗ (θ ) and λ A(θ ), we can calculate the
Now that we have the functions ω(θ1 ), π(θ1 ), θ2,C
1
1
E
expected wealth of shareholders for each grid-point of θ1 > 0; the graph of this mapping isplotted in Panel 5. Expected shareholder wealth, conditional on θ1 > 0, is maximized at∗∗
θ1,C= .104 (row (6) of Table 4), and in this case, CC-holders select θ2,C
= .022 in period 2∗∗(row (8) of Table 4), bringing the total mean-preserving spread to θ1,C + θ2,C
= .126.

To determine which action set is chosen by management (i.e., {θ1,E , θ2,E } = {0, .078} or{θ1,C , θ2,C } = {.104, .022}) we can overlay both shareholder-wealth functions (from Panels
2 and 5) and compare their peak values; this is done in Panel 6. Since action set {0, .078}
produces an expected shareholder wealth of .1175, while action set {.104, .022} produces an
expected shareholder wealth of .1247 (see rows (11) and (12) of Table 4, respectively), the“excessive” risk-taking equilibrium is arrived at, and aggregate risk shifting is .126.
Finally, for the sake of comparison, Figure 3 overlays the contents of Panel 6 with theshareholder-wealth function derived using equity’s book value as its reference value. Both∗
Note that π(θ1 ) and θ2,C(θ1 )’s kink-points at θ1 (%) = 3.1% are the result of the restriction θ2 ≥ θ1 ,which preserves a unit measure of probability.
28

22

Figure 2. Numerical results: Continuous Risk Shifting
Panel 1: Capital Requirement and Write-Downs

.13

.110

20

.105

10

.100
0

3

6

9

12

Shareholder Wealth30

ω(θ1) (%)

Capital Adequacy Ratio.115

Panel 2: Wealth: Shareholder Controlled

.12
.11
.10
.09

0
15

0

3

6

9

12

θ1 (%)

θ2 (%)

Panel 3: Equity Transfer

Panel 4: Period-2 Risk Shifting

15

8
4
3

θ*2,C(θ1) (%)π(θ1) (%)

6

4

2
1
0
-1

2

-2
0
0

3

6

9

12

-3
0

15

3

6

9

12

θ1 (%)

θ1 (%)

Panel 5: Wealth: CC-Holder Controlled

Panel 6: Overlay of Panels 2 & 5

15

.12

Shareholder Wealth

Shareholder Wealth

.13

.11
.10
.09

.12

.11
Shareholder Controlled →.10← CC-Holder Controlled

.09
.08
0

3

6

9

12

15

0

θ1 (%)

36
9
θ1 / θ2 (%)

12

15This figure plots the continuous risk-shifting numerical results. Panel 1: the bank’s capital-adequacy ratio(left axis), and the percentage of CC written down (right axis), as a function of θ1 (in percentage terms).
Panel 2: the relationship between shareholder wealth and θ2 (in percentage terms) when θ1 = 0. Panel
3: The percentage of equity transferred to CC-holders upon conversion, as a function of θ1 (in percentage
terms), when the bank uses equity’s market value as the reference value. Panel 4: the relationship between
period-2 risk shifting and θ1 > 0 (both in percentage terms). Panel 5: the relationship between shareholder
wealth and θ1 > 0 (in percentage terms). Panel 6: Overlay of Panels 2 and 5.

23

Table 4. Numerical Results: Continuous Risk Shifting
(1)
Book
Value

(2)
Market
Value

(1)
(2)

ω(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

0
18.0

0
20.1

(3)
(4)

π(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

0
9.0

0
6.3

(5)
(6)

θ1∗
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

0
.090

0
.104

(7)
(8)

θ2∗ (θ1 )Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

.078
.038

.078
.022

(9)
(10)

Final Equity Value
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

.1351
.1658

.1351
.1665

(11)
(12)

Expected Shareholder Wealth
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

.1175
.1274

.1175
.1247

This table reports the numerical results for the continuous risk-shifting case. Column (1) reports the setof results derived using a constant reference value (book value), while Column (2) reports the set of results
derived using equity’s market value. ω(θ1 )(%) is the percentage of CC written down, π(θ1 )(%) is thepercentage of equity transferred to CC-holders upon conversion, while θ2∗ (θ1 ) is the value of period-2 risk
shifting.

shareholder-wealth functions for θ1 > 0 are similar, and produce identical qualitative results - management selects the action set {θ1,C , θ2,C } in equilibrium. In the case of a fixedreference value, the equilibrium action set is {.09, .038}, and aggregate risk shifting is .128.
See column (1) of Table 4 for comparable results using the fixed-reference-value assumption.
See Appendix D for an alternative, but plausible, set of parameter values (where .05 of C isonce again substituted for D) that supports an “excessive” safety equilibrium for the caseof continuous risk shifting.

24

Figure 3. Shareholder Wealth When: θ1 = 0; and θ1 > 0, for both Reference-Value Assumptions.13

Shareholder Wealth

.12

.11

.10

.09

Shareholder Controlled
CC-Holder Controlled: Book Value
CC-Holder Controlled: Market Value

.08
0

3

6

9

12

15

θ 1 / θ 2 (%)
This figure plots the relationship between expected shareholder wealth and θ2 when shareholders retain
control (i.e., θ1 = 0), and the relationship between expected shareholder wealth and θ1 when CC-holders
gain control (i.e., θ1 > 0), for both reference-value assumptions.

6

Conclusion

Contingent-capital securities (CC) have the potential to mitigate lending disruptions causedby negative shocks to bank capital. However, they also have the potential to incentivize risktaking on the part of banks. This paper develops a model of banking to study this issue.
Shareholders in the model can influence bank risk taking in each period by way of theirequity-control rights. This is relevant for studying CC, because CC-investors become shareholders upon conversion, and can likewise influence risk taking via their newly-acquired
equity-control rights. A second building block of the model is that partial conversion of CC- just enough to regain capital-ratio compliance - leaves its holders with a portfolio of bankdebt and equity. In this way, CC-holder preferences for risk taking will rationally depend on
their relative holdings of bank debt and equity post-conversion: a higher (lower) proportionof equity will incentivize more (less) risk taking. These endogenous preferences will, in turn,
manifest themselves in post-conversion risk taking via endogenous CC-holder control rights.
In addition to affecting the level of risk taking post-conversion, these endogenous preferences and equity-control rights will affect the level of pre-conversion risk taking as well.
This operates through the wealth-maximizing behavior of rational shareholders, who will
anticipate these preferences, and can partially affect them via pre-conversion risk taking;since higher (lower) pre-conversion risk taking leads to higher (lower) capital requirements
via asset risk-weights, and therefore, higher (lower) levels of CC written off. Taken together,
the model has two distinct equilibria. In the first, shareholders engage in “excessive” risktaking, which increases the value of equity and creates a voting-block of risk-seeking CC-

25

holders that support further risk-taking initiatives. In the second, shareholders engage in“excessive” safety to avoid conversion altogether, thereby preventing the creation of an influential and risk-averse voting block.
The model is solved analytically, and comparative statics are run. These demonstratethat relatively high CC-to-equity ratios can reduce the likelihood of reaching an “excessive” risk-taking equilibrium, which provides a rational for substituting material quantities
of conventional bank debt with CC. On the other hand, the comparative statics provide
mixed results on the overall merits of higher capital requirements, and the optimal rate at
which CC is converted into equity.
In addition to providing an analytic solution, the paper also presents a set of numerical results based on reasonable parameter values; these provide an indication of each equilibria’s
feasibility.
Going forward, an interesting avenue of further study is the interaction among pre-existing
blockholders, and those blockholders created via CC conversion. In this paper’s first endeavor at studying endogenous CC-holder preferences and control rights, it used a fairly
narrow assumption regarding the dynamics of corporate-governance. As such, further refinements/extensions of this assumption may generate valuable new insights.29 The challenge,
however, is selecting an appropriate refinement. As pointed out in the blockholder literature, this is a non-trivial matter given the co-dependencies among blockholders with regard
to activism (see Edmans and Holderness 2017 for a discussion), the non-uniform propensityof investor-types to engage in activism (see Yermack (2010) and Edmans and Holderness(2017)) and the general opacity of blockholder activism (McCahery et al. (2016) makes
an important contribution in this respect by surveying institutional investors on their rolein corporate governance). Finally, in addition to leveraging insights from the blockholder
literature, that literature may also do well by studying CC, given the unique endogeneityof blockholder-creation it entails.30

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A

Proof of Additional CC-Holder Risk Taking

This is a sketch of the proof. Shareholders always have the option to prevent conversion in∗period 1, and select θ2,E
in period 2 (from Equation 4) - call this Case 1. If management
violates the bank’s CAR - call this Case 2 - aggregate risk shifting must be greater than
∗ : only then will the bank’s aggregate equity value in Case 2 exceed that in Case 1 (net
θ2,Eof the appreciation in equity value stemming from written-off CC - which accrues entirely
to CC-holders given the assumption r ≥ 1), which is necessary given shareholders dilute∗< 0 (i.e., CC-holders select a mean-preserving
their own equity holdings in Case 2. If θ2,C∗
(i.e., management selects acontraction upon acquiring control) it must be that θ1 > θ2,E∗
mean-preserving spread that exceeds θ2,E in period 1). However, this can never happen in∗∗
equilibrium since θ1 > θ2,E
is sub-optimal from Equation 4 when θ2,C
< 0. 

B

Proof of Optimal CC-Holder Risk Shifting Level

The aggregate value of equity and debt held by CC-holders, conditional on θ1 and θ2 , is:




 

(θ1 + θ2 )(θ1 + θ2 )π(θ1 ) 1 − 1 −(D + C(1 − ω(θ1 ))) + 1 −C(1 − ω(θ1 )),2
2from Expression 5. Rearranging this expression gives us:θ1 + θ 2
θ1 + θ2π
D − (1 − π)C(1 − ω) + C(1 − ω) + π(1 − D − C(1 − ω)),22
where the arguments of π(·) and ω(·) are suppressed for brevity. Only the first two components are affected by θ2 ; the first is increasing in θ2 - wealth extracted from depositors- while the second is decreasing - reduction in CC value, net of the corresponding appreciation in equity value. An increase in the CC-holder’s portfolio value, from an increasein θ2 , is highest when π = 1. If CC-holders select θ2 = 2θb instead of θ2 = θb when π = 1(i.e., increase portfolio risk when it is the most advantageous to do so) their wealth - net ofadjustment costs - changes by:
b −A
b < 0,−θC
b Conversely, an increase infrom Assumption 7. Therefore, CC-holders will never select 2θ.
the CC-holder’s portfolio value, from a decrease in θ2 , is highest in the limit as π → 0. If
CC-holders select θ2 = −2θb instead of θ2 = −θb as π → 0 (i.e., decrease portfolio risk when
it is the most advantageous to do so) their wealth - net of adjustment costs - changes by:
b −A
b<0
−θD
from Assumption 7 and the fact that π → 0 ⇐⇒ ω → 0. Therefore, CC-holders will neverb 
select −2θ.
30

C

Proof Supporting Corollary 2

The right-hand-side of condition:"

θ1∗ = 2θb

iff

#
b
θ
3rb
η θb2
b + C) −b − 2rb
θ(D(D + C) > 0(D + C) + Aη θb −
2
E1

can be rewritten as:




D
+
C
3rb
η
2
b
b
b+θ
−A
− 2rb
η −θ
(D + C) > 0.
2
E1
Both bracketed terms are positive under Assumptions 1 - 7, and therefore, this quadratic is
b As such, there exists a θbU suchconcave down, and necessarily negative for large enough θ.
U
∗
31
b 
that θb < θb is necessary for θ1 = 2θ.

D

Alternative Numerical Results

The following set of numerical results illustrate that substituting CC for conventional bankdebt can preclude the “excessive” risk-taking equilibria (leading to the “excessive” safety
equilibria instead). The only change from Section 5’s base-case parameterization is that .05
of C is substituted for D (i.e., CC is doubled). As before, the numerical results are derived
using both discrete and continuous risk shifting.

D.1

Discrete Risk Shifting

Table 5 reports the set of parameter values (changes in boldface) used for the discrete riskshifting case, and Table 6 reports the associated numerical results. These were derived
using both reference-value assumptions: the results contained in column (1) correspond to
the use of equity’s book value, while those contained in column (2) correspond to the useof equity’s market value.
Table 5. Alternative Parameter Values for the Discrete Risk-Shifting Numerical Results
Parameter

Value

Parameter
θb

Value

Xg

1

D

.8

0

.1

b
A(±θ)
b
A(±2θ)

C

.025

b
E1 /R

.1

λE

1

ηb

.1

λC

1

.05

This table reports the alternative parameter values used to derive the discrete risk-shifting numerical results.
The only change from the base-case parameterization is that .05 of C is substituted for D.

31

This condition is necessary but not sufficient. θb must also be large enough to compensate shareholdersb In addition, any θbU > 1/2 is not the least-upper-bound.
for A.

31

Table 6. Numerical Results: Discrete Risk Shifting (High CC-to-Equity Ratio)
(1)
Book
Value

(2)
Market
Value

(1)
(2)
(3)

ω(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

0
5
10

0
5
10

(4)
(5)
(6)

π(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

0
5
10

0
4.8
7.6

(7)
(8)
(9)

θ2∗ (θ1 )Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

.05
-.05
-.05

.05
-.05
-.05

(10)
(11)
(12)

Market Value of Equity
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

.1225
.1050
.1323

.1225
.1050
.1323

(13)
(14)
(15)

Expected Shareholder Wealth
Equity Controlled: θ1 = 0
CC Controlled: θ1 = 0.05
CC Controlled: θ1 = 0.1

.1225
.0998
.0940

.1225
.1000
.0973

This table reports the numerical results for the discrete risk-shifting case using the alternative parametervalues contained in Table 5. Column (1) reports the set of results derived using a constant reference value(book value), while Column (2) reports the set of results derived using equity’s market value. ω(θ1 )(%) is
the percentage of CC written down, π(θ1 )(%) is the percentage of equity transferred to CC-holders upon
conversion, while θ2∗ (θ1 ) is the value of period-2 risk shifting. All of the differences between the values inthis table and those of Table 3 are reported in boldface.

When the original face value of CC is increased by 100%, from .05 to .1, the percentage ofCC written down when θ1 = .05 (θ1 = .1) is reduced by 50%, from 10% (20%) to 5% (10%)(see rows (2) and (3) of Table 6). Since the book value of equity, and the absolute valueof CC written-down, are both unchanged from Section 5, it follows that the percentage ofequity transferred to CC-holders upon conversion remains unchanged as well when using thefirst reference-value assumption (book value), i.e., π(.05) = 5% and π(.1) = 10% (see rows(5) and (6) of Table 6). Under the second reference-value assumption (market value), both
the reference value of equity, and the percentage of equity transferred to CC-holders upon∗
conversion, are once again solutions to a fixed-point problem involving θ2,Cand equity’smarket value. In contrast to the base-case results, CC-holders in this situation optimally∗select a mean-preserving contraction in period 2 (i.e., θ2,C
= −.05) for both θ1 = .05 and32θ1 = .1, and they do this for both reference-value assumptions (see rows (8) and (9) of
Table 6). This follows from the relatively-large amount of outstanding CC post-conversion
compared with the amount of transferred equity (i.e., a relatively low ω(θ1 ) in comparison
with π(θ1 )). We know from Section 3 that management never permits CC-conversion when∗θ2,C
< 0; this implies that θ1 = 0 in period 1, and that the “excessive” safety equilibriumis achieved.
To see this result more clearly, note that equity’s market value when θ1 = .1 is .1323 (i.e., E1∗ )(D + C(1 − ω(θ ))/2 =(.1), plus the 10% of C that was written down (.01), plus (θ1 + θ2,C
1(.1 − .05)(.8 + .1(1 − .1))/2 = .0223 of wealth extracted from creditors via aggregate risk
shifting - see row (12) of Table 6).32 Therefore, π(.1) = 7.6 under the second referencevalue assumption (see row (6) of Table 6). Although more equity is transferred to CCholders under the alternative parameterization - due to equity’s lower market value - thepercentage of equity transferred is smaller relative to outstanding CC. This holds true forboth reference-value assumptions. In both of these cases N V (.1) < 0 from Equation 7, which∗ (.1) < 0 from Equation 8, and that θ ∗ (.1) = −.05 from Appendix B. In
implies that θ2,C
2,C
this situation, expected shareholders wealth is .094 (.0973) under the first (second) referencevalue assumption, as shareholders retain 90% (92.4%) of the bank’s equity in peirod 2, which
is worth .1323, and they also need to pay an adjustment cost of .025 for selecting θ1 = .1
(see rows (6), (12) and (15) of Table 6). Therefore, management optimally selects θ1 = 0,
which produces an expected shareholder wealth of .1225 (see rows (4), (10) and (14) of
Table 6).

D.2

Continuous Risk Shifting

As in Section 5, the first set of continuous risk-shifting numerical results are derived using
equity’s market value as it’s reference value. In addition, all parameter values and functional forms are carried-over from Section 5, except that .05 of C is substituted for D, as
before.
Panel 1 of Figure 4 plots the bank’s capital requirement as a function of θ1 (left axis); thisfunction is unchanged from Section 5. Similarly, when banks meet their capital requirements in period 2 (i.e., θ1 = 0), the level of expected shareholder wealth, as a functionof θ2 , remains unchanged also, since no CC is written down (see Panel 2).33 Therefore,∗
expected shareholder wealth is similarly maximized at θ2,E
= .078 (see row (7) of Table 7).
When banks fail to meet their capital requirements in period 2, the amount of CC writtendown for each θ1 > 0 remains unchanged. However, and importantly, the percentage ofCC written-off is reduced by 50% (right axis of Panel 1) since 100% more CC was issued.
Since a larger amount of CC is outstanding for each θ1 > 0, CC-holders are now more
inclined to select a mean-preserving contraction in period 2; thereby enhancing the value of
their outstanding CC. This can be seen from a comparison of Panel 4 from Figures 2 and32
Note that equity’s market value, the percentage of equity transferred to CC-holders upon conversion,∗and the expected wealth of shareholders, all remain unchanged when θ1 = .05, since θ2,C(.05) = −.05 as
before. Therefore, other than the percentage of CC written down, the numerical results are identical in thatcase.
33This follows from the fungibility of outstanding CC and deposits with respect to creditor-wealth extraction via asset substitution in period 2 (see footnote 22).

33

Figure 4. Numerical results: Continuous Risk Shifting (High CC-to-Equity Ratio)
Panel 2: Wealth: Shareholder Controlled

20

.115

15

.110

10

.105

.12

5

.100
0

5

10
θ1 (%)

15

Shareholder Wealth.120

ω(θ1) (%)

Capital Adequacy Ratio

Panel 1: Capital Requirement and Write-Downs

0
20

.11
.10
.09
.08
.07
0

Panel 3: Equity Transfer

15

20

2

8

0

θ*2,C(θ1) (%)π(θ1) (%)

10
θ2 (%)

Panel 4: Period-2 Risk Shifting

10

6
4

-2

-4

2
0
0

5

10
θ1 (%)

15

-6
0

20

Panel 5: Wealth: CC-Holder Controlled
.12

.12

.11

.11

.10
.09
.08
.07
0

5

10
θ1 (%)15510
θ1 (%)

15

20

Panel 6: Overlay of Panels 2 & 5

Shareholder Wealth

Shareholder Wealth5

Shareholder Controlled →.10.09← CC-Holder Controlled

.08
.07
0

20

5

10
θ1 / θ2 (%)

15

20This figure plots the continuous risk-shifting numerical results when .05 of C is substituted for D (comparedwith the base-case parameterization of Section 5). Panel 1: the bank’s capital-adequacy ratio (left axis),
and the percentage of CC written down (right axis), as a function of θ1 (in percentage terms). Panel 2: therelationship between shareholder wealth and θ2 (in percentage terms) when θ1 = 0. Panel 3: The percentageof equity transferred to CC-holders upon conversion, as a function of θ1 (in percentage terms), when thebank uses equity’s market value as the reference value. Panel 4: the relationship between period-2 risk
shifting and θ1 > 0 (both in percentage terms). Panel 5: the relationship between shareholder wealth andθ1 > 0 (in percentage terms). Panel 6: Overlay of Panels 2 and 5.

34

Table 7. Numerical Results: Continuous Risk Shifting (High CC-to-Equity Ratio)
(1)
Book
Value

(2)
Market
Value

(1)
(2)

ω(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

0
10.7

0
11.6

(3)
(4)

π(θ1 ) (%)
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

0
10.7

0
7.6

(5)
(6)

θ1∗
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

0
.107

0
.116

(7)
(8)

θ2∗ (θ1 )Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

.078
.005

.078
-.024

(9)
(10)

Final Equity Value
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

.1351
.1604

.1351
.1526

(11)
(12)

Expected Shareholder Wealth
Equity Controlled: θ1 = 0
CC Controlled: θ1 > 0

.1175
.1100

.1175
.1020

This table reports the numerical results for the continuous risk-shifting case. Column (1) reports the setof results derived using a constant reference value (book value), while Column (2) reports the set of results
derived using equity’s market value. ω(θ1 )(%) is the percentage of CC written down, π(θ1 )(%) is thepercentage of equity transferred to CC-holders upon conversion, while θ2∗ (θ1 ) is the value of period-2 risk
shifting. All of the differences between the values in this table and those of Table 4 are reported in boldface.

∗ (θ ). Notice that CC-holders acquire weakly-higher percentages of4, which both plot θ2,C
1
equity upon conversion for each θ1 > 0 (this can be seen from a comparison of Panel 3 from
Figures 2 and 4 - although it is somewhat hard to tell), due to equity’s weakly-lower market
value, as discussed shortly. However, in spite of this, CC-holders select mean-preserving∗ (θ ) fromcontractions over a wider range of θ1 , as indicated by the downward-shift in θ2,C
1
Panel 4. These mean-preserving contractions (and lower mean-preserving spreads when
∗ (θ ) > 0), act to reduce equity’s market value, and thus result in larger equity transfers.
θ2,C1This weakly-reduces the expected wealth of shareholders for every θ1 > 0 by: (1) reducing
equity’s market value, and (2) diluting shareholders to a greater extent. This is reflected inPanel 5, which plots expected shareholder wealth as function of θ1 > 0, which is noticeably
lower than its counterpart from Section 5 (Panel 5 of Figure 2). In this case, expected∗∗shareholder wealth is maximized at θ1,C
= .116, which induces θ2,C
= −.024 (see rows (6)and (8) of Table 7).

35∗ , θ ∗ } = {.116, −.024} cannot constitute an equiWe know from Appendix A that {θ1,C
2,C∗
librium action set since θ2,C
< 0. However, another way of seeing this is to overlay bothshareholder wealth functions (from Panels 2 and 5) and compare their peak values. Thisis done in Panel 6. As this figure illustrates, the shareholder-wealth function for θ1 = 0
achieves a higher maximum value than the shareholder-wealth function for θ1 > 0, and as∗ , θ ∗ } = {0, .078}, thus achieving the “excessuch, management selects the action set {θ1,E
2,E
sive” safety equilibrium.

Once again, for the sake of comparison, Figure 5 overlays the contents of Panel 6 from
Figure 4 with the shareholder-wealth function derived using equity’s book value as it’s reference value. As before, both shareholder-wealth functions for θ1 > 0 produce the sameequilibrium result - management selects the action set {θ1,E , θ2,E } in both cases. However,since more equity is transferred to CC-holders upon conversion in the second case (book∗> 0 (see row (8) of Table 7). That is, CC-holders select avalue) it turns out that θ2,C∗
is sufficiently low undermean-preserving spread in period 2.34 Even so, given that θ2,C
the alternative parameterization (compare row (8) of Tables 4 and 7), it is sub-optimal forshareholders to dilute their own equity stakes in order to achieve a higher aggregate equity
value (i.e., Component 5 of Expression 9 is sufficiently small in comparison to Component 1).
See column (1) of Table 7 for comparable results using the fixed-reference-value assumption.
Figure 5. Shareholder Wealth When: θ1 = 0; and θ1 > 0, for both Reference-Value Assumptions (High CC-to-Equity Ratio).12

Shareholder Wealth

.11

.10

.09

.08

Shareholder Controlled
CC-Holder Controlled: Book Value
CC-Holder Controlled: Market Value

.07
0

5

10

15

20

θ 1 / θ 2 (%)
This figure plots the relationship between expected shareholder wealth and θ2 when shareholders retain
control (i.e., θ1 = 0), and the relationship between expected shareholder wealth and θ1 when CC-holders
gain control (i.e., θ1 > 0), for both reference-value assumptions.
34∗
Note, however, that θ2,C(θ1 ) shifts downward for the second reference-value assumption also (see Panel
3 of Figure 4).

36