**Jul 3 JDN 2459783**

The copyright protection for Mickey Mouse is set to expire in 2024, though a recently-proposed bill that specifically targets large corporations would cause it to end immediately. Steamboat Willie was released in 1928.

This means that Mickey Mouse has been under copyright protection for 94 years, and is scheduled to last 96. Let me remind you that Walt Disney has been dead since 1966. This is, quite frankly, ridiculous. Mickey Mouse should have been released into the public domain decades ago.

Copyright *in general *has quite a shaky justification, and there are those who argue that it should be eliminated entirely. There’s something profoundly weird—and fundamentally monopolistic—about banning people from *copying *things.

But clearly we do need some way of ensuring that creators of artistic works can be fairly compensated for their efforts. Copyright is not the only way to do that: A few alternatives that I think are worth considering are expanded crowdfunding (Patreon and Kickstart already support quite a few artists, though most not very much), a large basic income (artists would still create even if they weren’t paid; they really just need money to live on), government grants directly to artists (we have the National Endowment for the Arts, but it doesn’t support very many artists), and some kind of central clearinghouse that surveys consumers about the art they enjoy and then compensates artists according to how much their work is appreciated. But all of these would require substantial changes, and suffer from their own flaws, so for the time being, let’s say we stick with copyright.

Even so, it’s utterly ludicrous that Disney has managed to hold onto the copyright on Mickey Mouse for this long. It makes absolutely no sense from the perspective of supporting artists—indeed, in this case the artist has been dead for over 50 years.

In fact, it wouldn’t even make sense if Walt Disney were still alive. (Not many people live 96 years past their first highly-successful creative work, but it’s at least *possible, *if you say published as a child and then lived to be a centenarian*.*) If the goal is to incentivize new creative art, the first few decades—indeed, the first few *years—*are clearly the most important for doing so.

To show why this is, I need to take a brief detour into finance, and the concept of a **net present value**.

As the saying goes: Time is money. $1 today is worth more than $1 a year from now. (And if you doubt this, let me remind you of the old joke: “I’ll give you $1 million dollars if you give me $100! Such a deal! Give me the $100 today, and I’ll give you $1 per year for the next million years.”)

The idea of a net present value is to precisely quantify the monetary value of time (or the **time value of money**), so that we can compare cashflows over time in a directly comparable way.

To compute a net present value, you need a **discount rate**. At a discount rate of *r, *an amount of money X that you get 1 year from now is worth X/(1+r). The discount rate should be positive, because money later is worth less than money now; this means that we want X/(1+r) < X, and therefore r > 0.

This is surprisingly hard to get precisely, but relatively easy to ballpark. A good guess is that it’s somewhere close to the prevailing interest rate, or maybe the average return on the stock market. It should definitely be at least the inflation rate. Right now inflation is running a little high (around 8%), so we’d want to use a relatively high discount rate currently, maybe 10% or 12%. But I think in a more typical scenario, something more like 5-6% would be a reasonable guess.

Once you have a discount rate, it’s pretty simple to figure out the net present value: Just add up all the future cashflows, each discounted by that discount rate for the time you have to wait for it.

So for instance if you get $100 per year for the next 5 years, this would be your net present value:

100/(1+r) + 100/(1+r)^2 + 100/(1+r)^3 + 100/(1+r)^4 + 100/(1+r)^5

If you get $50 this year, $60 next year, $70 the year after that, this would be your next present value:

50 + 60/(1+r) + 70/(1+r)^2

If the cashflow is the same X over time for some fixed amount of time T this can be collapsed into a single formula using a **geometric series**:

X (1 – (1+r)^(-T)) – 1)/r

This is really just a more compact way of adding up, X + X/(1+r) + X/(1+r)^2 + …; here, let’s do that example of $100 per year for 5 years, with r = 10%.

100/1.1 + 100/1.1^2 + 100/1.1^3 + 100/1.1^4 + 100/1.1^5 = $379

100 (1 – 1.1^(-5))/0.1 = $379

See, we get the same answer either way. Notice that this is less than $100 * 5 = $500, which is what we’d get if we had assumed that $1 a year from now is worth the same as $1 today. But it’s not *too *much less, because it’s only 5 years.

This formula allows us to consider what happens when the time interval becomes extremely long—even *infinite. *It gives us the power to ask the question, “What is the value of this *perpetual *cashflow?”

This feels a bit weird for individuals, since of course we die. We can have heirs, but rare indeed is the thousand-year dynasty. (The Imperial House of Japan does appear to have an unbroken hereditary line for the last 2000 years, but they’re basically alone in that.) But governments and corporations don’t have a lifespan, so it makes more sense for them. The US government was here 200 years ago, and may still be here 200 years from now. Oxford was here 900 years ago, and I see no particular reason to think it won’t still be here 900 years from now.

Since r > 0, (1+r)^(-T) gets smaller as T increases. As T approaches infinity, (1+r)^(-T) approaches zero. So for a perpetual cashflow, we can just make this term zero.

Thus, we can actually assess the value of $1 per year for the next million years! It is this:

1 (1-(1+r)^(10^6))/r

which is basically the same as this:

1/r

So if your discount rate is 10%, then $1 per year for 1 million years is worth about as much to you as $1/0.1 = $10 today. If your discount rate is 5%, it would be worth about $1/0.05 = $20 today. And suddenly it makes sense that you’re not willing to pay $100 for this deal.

What if the cashflow is changing? Then this formula won’t work. But if it’s simply a constant rate of growth, we can adjust for that. If the growth rate of the cashflow is *g, *so that you get X, then X (1+g), then x (1+g)^2, and so on, the formula becomes just a bit more complicated:

X (1-(1+r-g)^(-T))/(r-g)

So for instance if your cashflow grows at 6% per year and your discount rate is 10%, then it’s basically the same as if it didn’t grow at all but your discount rate is 4%. [This is actually an approximation, but it’s a pretty good one.] Let’s call this the *effective discount rate.*

For a perpetual cashflow, as long as r > g, this becomes:

X/(r-g)

With this in mind, let’s return to the question of copyright. How long should copyright protection last?

We want it to last long enough for artists to be fairly compensated for their work; but what does “fairly compensated” mean? Well, with the concept of a perpetual net present value in mind, we could quantify this as *the majority of all revenue that would be expected to be earned by a perpetual copyright.*

I think this is actually quite generous: We’re saying that you should get to keep the copyright long enough to get *most *of what you’d probably get if we allowed you to own it *forever. *In some cases this might actually result in a copyright that’s too long; but I don’t see how it could result in it being too short.

Mickey Mouse today earns about $3 million per year. That’s honestly amazing, to continue to rake in that much money after such a long period. But, adjusted for inflation, that’s actually quite a bit *less *than what he took in just a few years after his first films were released, nominally $1 million per year which comes to more like $19 million per year in today’s money.

This means that our discount rate is larger than our growth rate (r > g) even if r is just inflation; but in fact we should use a discount rate higher than inflation. Let’s use a plausible but slightly conservative discount rate of 5%.

To grow from nominally $1 million to nominally $3 million per year in 94 years means a growth rate of about 1% per year.

So, our effective discount rate is 4%.

Then, a perpetual copyright for Mickey Mouse should be worth approximately:

X/(r-g) = 10^6/(0.04) = $25 million

Yes, that’s right; an unending stream of over $1 million per year ends up being worth about the same as a single payment of $25 million way back in 1928.

But isn’t Mickey Mouse a “fictional billionare”, meaning his total income over his existence has been more than $1 billion? Sure. And indeed, at a discount rate of 5%, $1 billion today is worth about $10 million in 1928. So Mickey is indeed well above that. Even if I use Forbes’ higher estimate that Mickey Mouse has taken in $5.8 billion, that would still only be a net present value of $59 million in 1928.

Remember, *time is money. *When it takes this long to get a cashflow, it ends up worth substantially less.

So, if we were aiming to let Mickey earn half of his perpetual earnings in net present value, when should we have ended his copyright? By my estimate, when the net present value of earnings exceeded $12.5 million. If we use Forbes’s more generous estimate, when it exceeded $30 million.

So now let’s go back to the formula for a finite time horizon, and try to solve it for T, the time horizon. We want the net present value of the finite horizon to be half that of the infinite horizon:

X (1-(1+r-g)^(-T))/(r-g) = (X/2)/(r-g)

(1+r-g)^(-T) = 1/2

To solve this for T, I’ll need to use a **logarithm**, the inverse of an exponent.

T = ln(2)/ln(1+r – g)

This is a **doubling time***, *very analogous to a **half-life **in physics. Since logarithms are very difficult to do by hand, if you don’t have a scientific calculator handy, you can also approximate it by dividing the percentage into 69:

T = 69/(r-g)%

This is because ln(2) = 0.69…, and when r-g is a small percentage, ln(1+r-g) is about the same as r-g.

For an effective discount rate of 4%, this becomes:

T = ln(2)/ln(1.04) = 69/4 = 17

That is, only *seventeen years. *Even for a hugely successful long-running property like Mickey Mouse (in fact, *is *there really anything on a par with Mickey Mouse?), the majority of the net present value was earned in less than 20 years.

Indeed, it seems especially sensible in this case, because back then, *Walt Disney was still alive! *He could actually enjoy the fruits of his labors for that period. Now it’s all going to some faceless shareholders of a massive megacorporation, only a few of which are even Walt Disney’s heirs. Only about 3% of Disney shares are owned by anyone actually in the Disney family.

This gives us an answer to the question, “How long should copyrights last?”: About 20 years.

If we’d used a higher discount rate, it would be even shorter: at 10%, you get only 10 years.

And a lower discount rate simply isn’t plausible; inflation and stock market growth are both too fast for net present value to be discounted much less than 4% or 5%. Maybe you could go as low as 3%, which would be 23 years.

Does this accomplish the goal of copyrights—which, remember, was to fairly compensate artists and incentivize the creation of artistic works? I’d say so. They get half of what they would have gotten if we never released their work into the public domain, and I don’t think I’ve ever met an artist who could honestly say that they’d create something if they could hold onto the rights for 96 years, but not if they could for only 20 years. (Maybe they exist, but if so, they are rare.) Most artists really just want to be credited—not paid, *credited—*for their work and to make a decent living. 20 years is enough for that.

This means that our current copyright system keeps works out of public domain nearly *five times as long *as there is any real economic justification for.