“The Magic Of Compounding” – The Impact Of 1% Change In Rates On Total 2022 US Debt

zerohedge.com / By Tyler Durden / January 6, 2013

They say “be careful what you wish for”, and they are right. Because, in the neverending story of the American “recovery” which, sadly, never comes (although in its place we keep getting now biannual iterations of Quantitative Easing), the one recurring theme we hear over and over and over is to wait for the great rotation out of bonds and into stocks. Well, fine. Let it come. The question is what then and what happens to the US economy when rates do, finally and so overdue (for all those sellside analysts and media who have been a broken record on the topic for the past 3 years), go up. To answer just that question, which in a country that is currently at 103% debt/GDP and which will be at 109% by the end of 2013, we have decided to ignore the CBO’s farcical models and come up with our own. Our model is painfully simple, and just to give our readers a hands on feel, we have opened up the excel file for everyone to tinker with (however, unlike the CBO, we do realize that when calculating average interest, one needs to have circular references enabled so please do that before you open the model).

Our assumptions are also painfully simple:

i) grow 2012 year end GDP of ~$16 trillion at what is now widely accepted as the ‘New Normal’ 1.5% growth rate (this can be easily adjusted in the model);

ii) assume the primary deficit is a conservative and generous 6% of GDP because America will never,repeat never, address the true cause of soaring deficits: i.e., spending, which will only grow up in direct proportion with demographics but as we said, we are being generous (also adjustable), and

iii) sensitize for 3 interest rate scenarios: 2% blended cash interest; 3% blended cash interest and 5% blended cash interest.

And it is here that we get a reminder of a very key lesson, one that even the CBO admitted on Friday they had forgotten about, in what compounding truly looks like in a country that is far beyond the Reinhart-Rogoff critical threshold of 80% sovereign debt/GDP.

The bottom line: going from just 2% to 3% interest, will result in total 2022 debt rising from $31.4 trillion to $34.1 trillion; while jumping from 2% to just the long term historical average of 5%, would push total 2022 debt to increase by a whopping $9 trillion over the 2% interest rate base case to over $40 trillion in total debt!

Sadly, this is no “magic” – this is the reality that awaits the US.

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