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22 abril 2022

Aposte no Semibeta

 Bollerslev et al. (2022) mostram que é possível decompor o Beta do CAPM em 4 Semibetas definidos pela covariância entre o mercado e o ativo de retorno individual. Considere as quatro combinações possíveis de retornos positivos e negativos para o ativo individual e o mercado: ambos os retornos são positivos (o estado P), ambos negativo (N), sinal misto com retorno de mercado positivo (M+) e sinal misto com retorno de mercado negativo (M -).




A estrutura de média-variância sugere que a covariação decorrente dos dois estados onde o retorno de mercado é positivo (P e M+) não deve ganhar nenhum prêmio de risco. Por outro lado, qualquer covariância associada a relação negativa dos retornos de mercado e de ativos individuais (N) deve ser compensada ​​positivamente, enquanto a covariância decorrente de retornos negativos de mercado e retornos positivos de ativos individuais (M) deve ter um prêmio de risco negativo. Essa interpretação é resumida no gráfico abaixo:






A teoria de precificação de ativos de média-variância prevê que apenas dois dos semibetas devem ser precificados, sendo que um corresponde ao conjunto de covariância negativa (N) que tem um prêmio de risco positivo, e o outro está associada a um retorno negativo de mercado e um retorno postivo do ativo (M- ) que tem prêmio de risco negativo.

Os autores estimaram o prêmio de risco anualizado para N seja de cerca de 23%, enquanto o prêmio de risco anualizado para M   é de cerca de -9%, em comparação com um prêmio de risco para o CAPM de cerca de 4%. Essas descobertas empíricas se baseiam em semibetas realizados calculados a partir de duas décadas de dados intradiários de alta frequência do S&P 500. 

Eles mostram ainda que estratégias de negociação simples que apostam em N e contra M  
levam a índices de Sharpe que são mais do que o dobro do mercado. Levando em conta
custos de transação, essas estratégias também produzem alfas ajustados ao risco grandes e fortemente estatisticamente significativos. 

Resumindo, não aposte contra beta, aposte a favor e contra os semibetas certos.




18 abril 2022

Inflação e o fim de uma ilusão econômica

 Inflation’s return marks a tipping point. Demand has hit the brick wall of supply. Our economies are now producing all that they can. Moreover, this inflation is clearly rooted in excessively expansive fiscal policies. While supply shocks can raise the price of one thing relative to others, they do not raise all prices and wages together. 

A lot of wishful thinking will have to be abandoned, starting with the idea that governments can borrow or print as much money as they need to spray at every problem. Government spending must now come from current tax revenues or from credible future tax revenues, to support non-inflationary borrowing. 

Stimulus spending for its own sake is over. Governments must start spending wisely. Spending to “create jobs” is nonsense when there is a widespread labor shortage. 

Unfortunately, many governments are responding to inflation by borrowing or printing even more money to subsidize energy, housing, childcare, and other costs, or to hand out more money to cushion the blow from inflation – for example, by forgiving student loans. These policies will lead to even more inflation. 

Expanded social programs and transfers must be funded from stable long-run tax revenues, from taxes that do not impose undue costs on the economy. These facts will make it much more difficult for policymakers to continue ignoring budgets and the disincentives that are embedded in many social programs. 

The bailout bandwagon will end. The 2008 financial crisis was met with a torrent of borrowed and printed money to stimulate the economy and bail out banks and their creditors. The COVID-19 recession was met with a tidal wave. Once again, government money went to bail out creditors, prop up asset prices, and provide more stimulus. 

Given these precedents, our financial system now firmly trusts that the government will borrow or print money in the event of any future crisis. But once fiscal space has run out and given way to inflation, the government’s ability to stop the next crisis may evaporate. When people no longer have confidence that the borrowed money will be repaid, or that the printed money will be soaked up again, they will not lend more. Today’s small (so far) inflation is a taste of this fundamental change. 

The “secular stagnation” debate is settled. Since 2000, long-term growth has fallen by half, representing one of the great unsung economic tragedies of the twenty-first century. After rising by an average of 3.6% per year between 1947 and 2000, US real (inflation-adjusted) GDP growth has since averaged just 1.8% per year. 

Was this sclerosis a case of demand-side “secular stagnation” that, given persistently low interest rates, had to be addressed with oodles of “fiscal stimulus?” Or did it follow from a reduction in supply owing to the corrosive effects of protected and over-regulated industries, or to deeper problems such as the erosion of educational performance or a lack of innovation? 

We now know that it was supply, and that more stimulus will bring only more inflation. If we want growth – to reduce poverty; to pay for health, environmental protections, and transfers; or for its own sake – it will have to come from unleashing supply. Tariffs, industrial protections, labor-market distortions, restrictions on skilled immigration, and other supply-constraining policies have direct costs that cannot be offset by printing more money. 

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The era of wishful thinking is over. Those who come to grips with that fact now will look a lot less foolish in the future.