Archives For markets
Drug makers recently announced their 2019 price increases on over 250 prescription drugs. As examples, AbbVie Inc. increased the price of the world’s top-selling drug Humira by 6.2 percent, and Hikma Pharmaceuticals increased the price of blood-pressure medication Enalaprilat by more than 30 percent. Allergan reported an average increase across its portfolio of drugs of 3.5 percent; although the drug maker is keeping most of its prices the same, it raised the prices on 27 drugs by 9.5 percent and on another 24 drugs by 4.9 percent. Other large drug makers, such as Novartis and Pfizer, will announce increases later this month.
So far, the number of price increases is significantly lower than last year when drug makers increased prices on more than 400 drugs. Moreover, on the drugs for which prices did increase, the average price increase of 6.3 percent is only about half of the average increase for drugs in 2018. Nevertheless, some commentators have expressed indignation and President Trump this week summoned advisors to the White House to discuss the increases. However, commentators and the administration should keep in mind what the price increases actually mean and the numerous players that are responsible for increasing drug prices.
First, it is critical to emphasize the difference between drug list prices and net prices. The drug makers recently announced increases in the list, or “sticker” prices, for many drugs. However, the list price is usually very different from the net price that most consumers and/or their health plans actually pay, which depends on negotiated discounts and rebates. For example, whereas drug list prices increased by an average of 6.9 percent in 2017, net drug prices after discounts and rebates increased by only 1.9 percent. The differential between the growth in list prices and net prices has persisted for years. In 2016 list prices increased by 9 percent but net prices increased by 3.2 percent; in 2015 list prices increased by 11.9 percent but net prices increased by 2.4 percent, and in 2014 list price increases peaked at 13.5 percent but net prices increased by only 4.3 percent.
For 2019, the list price increases for many drugs will actually translate into very small increases in the net prices that consumers actually pay. In fact, drug maker Allergan has indicated that, despite its increase in list prices, the net prices that patients actually pay will remain about the same as last year.
One might wonder why drug makers would bother to increase list prices if there’s little to no change in net prices. First, at least 40 percent of the American prescription drug market is subject to some form of federal price control. As I’ve previously explained, because these federal price controls generally require percentage rebates off of average drug prices, drug makers have the incentive to set list prices higher in order to offset the mandated discounts that determine what patients pay.
Further, as I discuss in a recent Article, the rebate arrangements between drug makers and pharmacy benefit managers (PBMs) under many commercial health plans create strong incentives for drug makers to increase list prices. PBMs negotiate rebates from drug manufacturers in exchange for giving the manufacturers’ drugs preferred status on a health plan’s formulary. However, because the rebates paid to PBMs are typically a percentage of a drug’s list price, drug makers are compelled to increase list prices in order to satisfy PBMs’ demands for higher rebates. Drug makers assert that they are pressured to increase drug list prices out of fear that, if they do not, PBMs will retaliate by dropping their drugs from the formularies. The value of rebates paid to PBMs has doubled since 2012, with drug makers now paying $150 billion annually. These rebates have grown so large that, today, the drug makers that actually invest in drug innovation and bear the risk of drug failures receive only 39 percent of the total spending on drugs, while 42 percent of the spending goes to these pharmaceutical middlemen.
Although a portion of the increasing rebate dollars may eventually find its way to patients in the form of lower co-pays, many patients still suffer from the list prices increases. The 29 million Americans without drug plan coverage pay more for their medications when list prices increase. Even patients with insurance typically have cost-sharing obligations that require them to pay 30 to 40 percent of list prices. Moreover, insured patients within the deductible phase of their drug plan pay the entire higher list price until they meet their deductible. Higher list prices jeopardize patients’ health as well as their finances; as out-of-pocket costs for drugs increase, patients are less likely to adhere to their medication routine and more likely to abandon their drug regimen altogether.
Policymakers must realize that the current system of government price controls and distortive rebates creates perverse incentives for drug makers to continue increasing drug list prices. Pointing the finger at drug companies alone for increasing prices does not represent the problem at hand.
A recent NBER working paper by Gutiérrez & Philippon has attracted attention from observers who see oligopoly everywhere and activists who want governments to more actively “manage” competition. The analysis in the paper is fundamentally flawed and should not be relied upon by policymakers, regulators, or anyone else.
As noted in my earlier post, Gutiérrez & Philippon attempt to craft a causal linkage between differences in U.S. and EU antitrust enforcement and product market regulation to differences in market concentration and corporate profits. Their paper’s abstract leads with a bold assertion:
Until the 1990’s, US markets were more competitive than European markets. Today, European markets have lower concentration, lower excess profits, and lower regulatory barriers to entry.
This post focuses on Gutiérrez & Philippon’s claim that EU markets have lower “excess profits.” This is perhaps the most outrageous claim in the paper. If anyone bothers to read the full paper, they’ll see that claims that EU firms have lower excess profits is simply not supported by the paper itself. Aside from a passing mention of someone else’s work in a footnote, the only mention of “excess profits” is in the paper’s headline-grabbing abstract.
What’s even more outrageous is the authors don’t define (or even describe) what they mean by excess profits.
These two factors alone should be enough to toss aside the paper’s assertion about “excess” profits. But, there’s more.
Gutiérrez & Philippon define profit to be gross operating surplus and mixed income (known as “GOPS” in the OECD’s STAN Industrial Analysis dataset). GOPS is not the same thing as gross margin or gross profit as used in business and finance (for example GOPS subtracts wages, but gross margin does not). The EU defines GOPS as (emphasis added):
Operating surplus is the surplus (or deficit) on production activities before account has been taken of the interest, rents or charges paid or received for the use of assets. Mixed income is the remuneration for the work carried out by the owner (or by members of his family) of an unincorporated enterprise. This is referred to as ‘mixed income’ since it cannot be distinguished from the entrepreneurial profit of the owner.
Here’s Figure 1 from Gutiérrez & Philippon plotting GOPS as a share of gross output.
Look at the huge jump in gross operating surplus for U.S. firms!
Now, look at the scale of the y-axis. Not such a big jump after all.
Over 23 years, from 1992 to 2015, the gross operating surplus rate for U.S. firms grew by 2.5 percentage points. In the EU, the rate increased by about one percentage point.
Using the STAN dataset, I plotted the gross operating surplus rate for each EU country (blue dots) and the U.S. (red dots), along with a time trend. Three takeaways:
- There’s not much of a difference between the U.S. and the EU average—they both hover around a gross operating surplus rate of about 19.5 percent; and
- There’s a huge variation in gross operating surplus rate across EU countries.
- Yes, gross operating surplus is trending slightly upward in the U.S. and slightly downward for the EU average, but there doesn’t appear to be a huge difference in the slope of the trendlines. In fact the slopes of the trendlines are not statistically significantly different from zero and are not statistically significantly different from each other.
The use of gross profits raises some serious questions. For example, the Stigler Center’s James Traina finds that, after accounting for selling, general, and administrative expenses (SG&A), mark-ups for publicly traded firms in the U.S. have not meaningfully increased since 1980.
The figure below plots net operating surplus (NOPS equals GOPS minus consumption of fixed capital)—which is not the same thing as net income for a business.
Same three takeaways:
- There’s not much of a difference between the U.S. and the EU average—they both hover around a net operating surplus rate of a little more than seven percent; and
- There’s a huge variation in net operating surplus rate across EU countries.
- The slope of the trendlines for net operating surplus in the U.S. and EU are not statistically significantly different from zero and are not statistically significantly different from each other.
It’s very possible that U.S. firms are achieving higher and growing “excess” profits relative to EU firms. It’s also very possible they’re not. Despite the bold assertions of Gutiérrez & Philippon, the information presented in their paper provides no useful information one way or the other.
A recent NBER working paper by Gutiérrez & Philippon attempts to link differences in U.S. and EU antitrust enforcement and product market regulation to differences in market concentration and corporate profits. The paper’s abstract begins with a bold assertion:
Until the 1990’s, US markets were more competitive than European markets. Today, European markets have lower concentration, lower excess profits, and lower regulatory barriers to entry.
The authors are not clear what they mean by lower, however its seems they mean lower today relative to the 1990s.
This blog post focuses on the first claim: “Today, European markets have lower concentration …”
At the risk of being pedantic, Gutiérrez & Philippon’s measures of market concentration for which both U.S. and EU data are reported cover the period from 1999 to 2012. Thus, “the 1990s” refers to 1999, and “today” refers to 2012, or six years ago.
The table below is based on Figure 26 in Gutiérrez & Philippon. In 2012, there appears to be no significant difference in market concentration between the U.S. and the EU, using either the 8-firm concentration ratio or HHI. Based on this information, it cannot be concluded broadly that EU sectors have lower concentration than the U.S.
|CR8||26% (+5%)||27% (-7%)|
|HHI||640 (+150)||600 (-190)|
Gutiérrez & Philippon focus on the change in market concentration to draw their conclusions. However, the levels of market concentration measures are strikingly low. In all but one of the industries (telecommunications) in Figure 27 of their paper, the 8-firm concentration ratios for the U.S. and the EU are below 40 percent. Similarly, the HHI measures reported in the paper are at levels that most observers would presume to be competitive. In addition, in 7 of the 12 sectors surveyed, the U.S. 8-firm concentration ratio is lower than in the EU.
The numbers in parentheses in the table above show the change in the measures of concentration since 1999. The changes suggests that U.S. markets have become more concentrated and EU markets have become less concentrated. But, how significant are the changes in concentration?
A simple regression of the relationship between CR8 and a time trend finds that in the EU, CR8 has decreased an average of 0.5 percentage point a year, while the U.S. CR8 increased by less than 0.4 percentage point a year from 1999 to 2012. Tucked in an appendix to Gutiérrez & Philippon, Figure 30 shows that CR8 in the U.S. had decreased by about 2.5 percentage points from 2012 to 2014.
A closer examination of Gutiérrez & Philippon’s 8-firm concentration ratio for the EU shows that much of the decline in EU market concentration occurred over the 1999-2002 period. After that, the change in CR8 for the EU is not statistically significantly different from zero.
A regression of the relationship between HHI and a time trend finds that in the EU, HHI has decreased an average of 12.5 points a year, while the U.S. HHI increased by less than 16.4 points a year from 1999 to 2012.
As with CR8, a closer examination of Gutiérrez & Philippon’s HHI for the EU shows that much of the decline in EU market concentration occurred over the 1999-2002 period. After that, the change in HHI for the EU is not statistically significantly different from zero.
Readers should be cautious in relying on Gutiérrez & Philippon’s data to conclude that the U.S. is “drifting” toward greater market concentration while the EU is “drifting” toward lower market concentration. Indeed, the limited data presented in the paper point toward a convergence in market concentration between the two regions.
Last week, the DOJ cleared the merger of CVS Health and Aetna (conditional on Aetna’s divesting its Medicare Part D business), a merger that, as I previously noted at a House Judiciary hearing, “presents a creative effort by two of the most well-informed and successful industry participants to try something new to reform a troubled system.” (My full testimony is available here).
Of course it’s always possible that the experiment will fail — that the merger won’t “revolutioniz[e] the consumer health care experience” in the way that CVS and Aetna are hoping. But it’s a low (antitrust) risk effort to address some of the challenges confronting the healthcare industry — and apparently the DOJ agrees.
I discuss the weakness of the antitrust arguments against the merger at length in my testimony. What I particularly want to draw attention to here is how this merger — like many vertical mergers — represents business model innovation by incumbents.
The CVS/Aetna merger is just one part of a growing private-sector movement in the healthcare industry to adopt new (mostly) vertical arrangements that seek to move beyond some of the structural inefficiencies that have plagued healthcare in the United States since World War II. Indeed, ambitious and interesting as it is, the merger arises amidst a veritable wave of innovative, vertical healthcare mergers and other efforts to integrate the healthcare services supply chain in novel ways.
These sorts of efforts (and the current DOJ’s apparent support for them) should be applauded and encouraged. I need not rehash the economic literature on vertical restraints here (see, e.g., Lafontaine & Slade, etc.). But especially where government interventions have already impaired the efficient workings of a market (as they surely have, in spades, in healthcare), it is important not to compound the error by trying to micromanage private efforts to restructure around those constraints.
Current trends in private-sector-driven healthcare reform
In the past, the most significant healthcare industry mergers have largely been horizontal (i.e., between two insurance providers, or two hospitals) or “traditional” business model mergers for the industry (i.e., vertical mergers aimed at building out managed care organizations). This pattern suggests a sort of fealty to the status quo, with insurers interested primarily in expanding their insurance business or providers interested in expanding their capacity to provide medical services.
Today’s health industry mergers and ventures seem more frequently to be different in character, and they portend an industry-wide experiment in the provision of vertically integrated healthcare that we should enthusiastically welcome.
Drug pricing and distribution innovations
To begin with, the CVS/Aetna deal, along with the also recently approved Cigna-Express Scripts deal, solidifies the vertical integration of pharmacy benefit managers (PBMs) with insurers.
But a number of other recent arrangements and business models center around relationships among drug manufacturers, pharmacies, and PBMs, and these tend to minimize the role of insurers. While not a “vertical” arrangement, per se, Walmart’s generic drug program, for example, offers $4 prescriptions to customers regardless of insurance (the typical generic drug copay for patients covered by employer-provided health insurance is $11), and Walmart does not seek or receive reimbursement from health plans for these drugs. It’s been offering this program since 2006, but in 2016 it entered into a joint buying arrangement with McKesson, a pharmaceutical wholesaler (itself vertically integrated with Rexall pharmacies), to negotiate lower prices. The idea, presumably, is that Walmart will entice consumers to its stores with the lure of low-priced generic prescriptions in the hope that they will buy other items while they’re there. That prospect presumably makes it worthwhile to route around insurers and PBMs, and their reimbursements.
Meanwhile, both Express Scripts and CVS Health (two of the country’s largest PBMs) have made moves toward direct-to-consumer sales themselves, establishing pricing for a small number of drugs independently of health plans and often in partnership with drug makers directly.
Also apparently focused on disrupting traditional drug distribution arrangements, Amazon has recently purchased online pharmacy PillPack (out from under Walmart, as it happens), and with it received pharmacy licenses in 49 states. The move introduces a significant new integrated distributor/retailer, and puts competitive pressure on other retailers and distributors and potentially insurers and PBMs, as well.
Whatever its role in driving the CVS/Aetna merger (and I believe it is smaller than many reports like to suggest), Amazon’s moves in this area demonstrate the fluid nature of the market, and the opportunities for a wide range of firms to create efficiencies in the market and to lower prices.
At the same time, the differences between Amazon and CVS/Aetna highlight the scope of product and service differentiation that should contribute to the ongoing competitiveness of these markets following mergers like this one.
While Amazon inarguably excels at logistics and the routinizing of “back office” functions, it seems unlikely for the foreseeable future to be able to offer (or to be interested in offering) a patient interface that can rival the service offerings of a brick-and-mortar CVS pharmacy combined with an outpatient clinic and its staff and bolstered by the capabilities of an insurer like Aetna. To be sure, online sales and fulfillment may put price pressure on important, largely mechanical functions, but, like much technology, it is first and foremost a complement to services offered by humans, rather than a substitute. (In this regard it is worth noting that McKesson has long been offering Amazon-like logistics support for both online and brick-and-mortar pharmacies. “‘To some extent, we were Amazon before it was cool to be Amazon,’ McKesson CEO John Hammergren said” on a recent earnings call).
Other efforts focus on integrating insurance and treatment functions or on bringing together other, disparate pieces of the healthcare industry in interesting ways — all seemingly aimed at finding innovative, private solutions to solve some of the costly complexities that plague the healthcare market.
Walmart, for example, announced a deal with Quest Diagnostics last year to experiment with offering diagnostic testing services and potentially other basic healthcare services inside of some Walmart stores. While such an arrangement may simply be a means of making doctor-prescribed diagnostic tests more convenient, it may also suggest an effort to expand the availability of direct-to-consumer (patient-initiated) testing (currently offered by Quest in Missouri and Colorado) in states that allow it. A partnership with Walmart to market and oversee such services has the potential to dramatically expand their use.
Capping off (for now) a buying frenzy in recent years that included the purchase of PBM, CatamaranRx, UnitedHealth is seeking approval from the FTC for the proposed merger of its Optum unit with the DaVita Medical Group — a move that would significantly expand UnitedHealth’s ability to offer medical services (including urgent care, outpatient surgeries, and health clinic services), give it a significant group of doctors’ clinics throughout the U.S., and turn UnitedHealth into the largest employer of doctors in the country. But of course this isn’t a traditional managed care merger — it represents a significant bet on the decentralized, ambulatory care model that has been slowly replacing significant parts of the traditional, hospital-centric care model for some time now.
And, perhaps most interestingly, some recent moves are bringing together drug manufacturers and diagnostic and care providers in innovative ways. Swiss pharmaceutical company, Roche, announced recently that “it would buy the rest of U.S. cancer data company Flatiron Health for $1.9 billion to speed development of cancer medicines and support its efforts to price them based on how well they work.” Not only is the deal intended to improve Roche’s drug development process by integrating patient data, it is also aimed at accommodating efforts to shift the pricing of drugs, like the pricing of medical services generally, toward an outcome-based model.
Similarly interesting, and in a related vein, early this year a group of hospital systems including Intermountain Health, Ascension, and Trinity Health announced plans to begin manufacturing generic prescription drugs. This development further reflects the perceived benefits of vertical integration in healthcare markets, and the move toward creative solutions to the unique complexity of coordinating the many interrelated layers of healthcare provision. In this case,
[t]he nascent venture proposes a private solution to ensure contestability in the generic drug market and consequently overcome the failures of contracting [in the supply and distribution of generics]…. The nascent venture, however it solves these challenges and resolves other choices, will have important implications for the prices and availability of generic drugs in the US.
More enforcement decisions like CVS/Aetna and Bayer/Monsanto; fewer like AT&T/Time Warner
In the face of all this disruption, it’s difficult to credit anticompetitive fears like those expressed by the AMA in opposing the CVS-Aetna merger and a recent CEA report on pharmaceutical pricing, both of which are premised on the assumption that drug distribution is unavoidably dominated by a few PBMs in a well-defined, highly concentrated market. Creative arrangements like the CVS-Aetna merger and the initiatives described above (among a host of others) indicate an ease of entry, the fluidity of traditional markets, and a degree of business model innovation that suggest a great deal more competitiveness than static PBM market numbers would suggest.
This kind of incumbent innovation through vertical restructuring is an increasingly important theme in antitrust, and efforts to tar such transactions with purported evidence of static market dominance is simply misguided.
While the current DOJ’s misguided (and, remarkably, continuing) attempt to stop the AT&T/Time Warner merger is an aberrant step in the wrong direction, the leadership at the Antitrust Division generally seems to get it. Indeed, in spite of strident calls for stepped-up enforcement in the always-controversial ag-biotech industry, the DOJ recently approved three vertical ag-biotech mergers in fairly rapid succession.
As I noted in a discussion of those ag-biotech mergers, but equally applicable here, regulatory humility should continue to carry the day when it comes to structural innovation by incumbent firms:
But it is also important to remember that innovation comes from within incumbent firms, as well, and, often, that the overall level of innovation in an industry may be increased by the presence of large firms with economies of scope and scale.
In sum, and to paraphrase Olympia Dukakis’ character in Moonstruck: “what [we] don’t know about [the relationship between innovation and market structure] is a lot.”
What we do know, however, is that superficial, concentration-based approaches to antitrust analysis will likely overweight presumed foreclosure effects and underweight innovation effects.
We shouldn’t fetishize entry, or access, or head-to-head competition over innovation, especially where consumer welfare may be significantly improved by a reduction in the former in order to get more of the latter.
As Thom previously posted, he and I have a new paper explaining The Case for Doing Nothing About Common Ownership of Small Stakes in Competing Firms. Our paper is a response to cries from the likes of Einer Elhauge and of Eric Posner, Fiona Scott Morton, and Glen Weyl, who have called for various types of antitrust action to reign in what they claim is an “economic blockbuster” and “the major new antitrust challenge of our time,” respectively. This is the first in a series of posts that will unpack some of the issues and arguments we raise in our paper.
At issue is the growth in the incidence of common-ownership across firms within various industries. In particular, institutional investors with broad portfolios frequently report owning small stakes in a number of firms within a given industry. Although small, these stakes may still represent large block holdings relative to other investors. This intra-industry diversification, critics claim, changes the managerial objectives of corporate executives from aggressively competing to increase their own firm’s profits to tacitly colluding to increase industry-level profits instead. The reason for this change is that competition by one firm comes at a cost of profits from other firms in the industry. If investors own shares across firms, then any competitive gains in one firm’s stock are offset by competitive losses in the stocks of other firms in the investor’s portfolio. If one assumes corporate executives aim to maximize total value for their largest shareholders, then managers would have incentive to soften competition against firms with which they share common ownership. Or so the story goes (more on that in a later post.)
Elhague and Posner, et al., draw their motivation for new antitrust offenses from a handful of papers that purport to establish an empirical link between the degree of common ownership among competing firms and various measures of softened competitive behavior, including airline prices, banking fees, executive compensation, and even corporate disclosure patterns. The paper of most note, by José Azar, Martin Schmalz, and Isabel Tecu and forthcoming in the Journal of Finance, claims to identify a causal link between the degree of common ownership among airlines competing on a given route and the fares charged for flights on that route.
Measuring common ownership with MHHI
Azar, et al.’s airline paper uses a metric of industry concentration called a Modified Herfindahl–Hirschman Index, or MHHI, to measure the degree of industry concentration taking into account the cross-ownership of investors’ stakes in competing firms. The original Herfindahl–Hirschman Index (HHI) has long been used as a measure of industry concentration, debuting in the Department of Justice’s Horizontal Merger Guidelines in 1982. The HHI is calculated by squaring the market share of each firm in the industry and summing the resulting numbers.
The MHHI is rather more complicated. MHHI is composed of two parts: the HHI measuring product market concentration and the MHHI_Delta measuring the additional concentration due to common ownership. We offer a step-by-step description of the calculations and their economic rationale in an appendix to our paper. For this post, I’ll try to distill that down. The MHHI_Delta essentially has three components, each of which is measured relative to every possible competitive pairing in the market as follows:
- A measure of the degree of common ownership between Company A and Company -A (Not A). This is calculated by multiplying the percentage of Company A shares owned by each Investor I with the percentage of shares Investor I owns in Company -A, then summing those values across all investors in Company A. As this value increases, MHHI_Delta goes up.
- A measure of the degree of ownership concentration in Company A, calculated by squaring the percentage of shares owned by each Investor I and summing those numbers across investors. As this value increases, MHHI_Delta goes down.
- A measure of the degree of product market power exerted by Company A and Company -A, calculated by multiplying the market shares of the two firms. As this value increases, MHHI_Delta goes up.
This process is repeated and aggregated first for every pairing of Company A and each competing Company -A, then repeated again for every other company in the market relative to its competitors (e.g., Companies B and -B, Companies C and -C, etc.). Mathematically, MHHI_Delta takes the form:
where the Ss represent the firm market shares of, and Betas represent ownership shares of Investor I in, the respective companies A and -A.
As the relative concentration of cross-owning investors to all investors in Company A increases (i.e., the ratio on the right increases), managers are assumed to be more likely to soften competition with that competitor. As those two firms control more of the market, managers’ ability to tacitly collude and increase joint profits is assumed to be higher. Consequently, the empirical research assumes that as MHHI_Delta increases, we should observe less competitive behavior.
And indeed that is the “blockbuster” evidence giving rise to Elhauge’s and Posner, et al.,’s arguments For example, Azar, et. al., calculate HHI and MHHI_Delta for every US airline market–defined either as city-pairs or departure-destination pairs–for each quarter of the 14-year time period in their study. They then regress ticket prices for each route against the HHI and the MHHI_Delta for that route, controlling for a number of other potential factors. They find that airfare prices are 3% to 7% higher due to common ownership. Other papers using the same or similar measures of common ownership concentration have likewise identified positive correlations between MHHI_Delta and their respective measures of anti-competitive behavior.
Problems with the problem and with the measure
We argue that both the theoretical argument underlying the empirical research and the empirical research itself suffer from some serious flaws. On the theoretical side, we have two concerns. First, we argue that there is a tremendous leap of faith (if not logic) in the idea that corporate executives would forgo their own self-interest and the interests of the vast majority of shareholders and soften competition simply because a small number of small stakeholders are intra-industry diversified. Second, we argue that even if managers were so inclined, it clearly is not the case that softening competition would necessarily be desirable for institutional investors that are both intra- and inter-industry diversified, since supra-competitive pricing to increase profits in one industry would decrease profits in related industries that may also be in the investors’ portfolios.
On the empirical side, we have concerns both with the data used to calculate the MHHI_Deltas and with the nature of the MHHI_Delta itself. First, the data on institutional investors’ holdings are taken from Schedule 13 filings, which report aggregate holdings across all the institutional investor’s funds. Using these data masks the actual incentives of the institutional investors with respect to investments in any individual company or industry. Second, the construction of the MHHI_Delta suffers from serious endogeneity concerns, both in investors’ shareholdings and in market shares. Finally, the MHHI_Delta, while seemingly intuitive, is an empirical unknown. While HHI is theoretically bounded in a way that lends to interpretation of its calculated value, the same is not true for MHHI_Delta. This makes any inference or policy based on nominal values of MHHI_Delta completely arbitrary at best.
We’ll expand on each of these concerns in upcoming posts. We will then take on the problems with the policy proposals being offered in response to the common ownership ‘problem.’