Compound-Interest Time Travel Gambit

"$100 placed at 7 percent interest compounded quarterly for 200 years will increase to more than $100,000,000 — by which time it will be worth nothing."

— Lazarus Long, in Time Enough for Love by Robert A. Heinlein

It's the simplest way to turn time into money: drop a few dollars into a compound interest bank account, then hop into your Time-O-Matic or become Human Popsicles and come back in a couple dozen decades to find that your pocket change has exponentially increased to a fairly tidy fortune.

Of course, this particular moneymaking scheme is dependent on a number of preconditions at both ends of your time journey:

1. No world-spanning disaster, including a massive financial crisis, occurs and renders all forms of money worthless or nearly so.
2. Ridiculous Future Inflation doesn't counteract the effects of compound interest, meaning that you only get slightly richer at the end.
3. The financial institution in which your dollars are stored never becomes bankrupt or closes in the intervening years.
4. In your prolonged absence from reality, your assets aren't seized under laws of escheatment.
5. Said financial institution doesn't have a 'no time travelers' policy to prevent this kind of scheme from occurring.
6. The bank doesn't unilaterally change the conditions of the account, so bank fees would eat away more or less of your benefits.
7. The world will never adopt a post-capitalist economy where money as we know it becomes completely devalued; if so, say goodbye to that investment.
8. Your money is invested very wisely, and not into say, Enron or Lehman Brothers or K-Mart.
9. The economy continues to grow. The economy was mainly stagnant for most of human history, as was the population. Both only boomed during the Industrial Revolution. It's quite possible that if human population growth stops, the resources of humans are finite, or technological breakthroughs plateau that future economic growth will be very limited, if it even occurs.
10. Tax laws do not change in a manner that ensures that your fortune in capital gains does not place you in a tax bracket where the IRS or local equivalent immediately seizes everything.
11. That no con artist has realized that there's a fortune being stashed in an untouched bank account and tries to claim it for themselves, on the logic that if nobody's using the money, nobody will notice if it is stolen.
12. You can actually convince someone at the bank that you are somebody who is entitled to withdraw money from an account that hasn't been touched in generations and not a con artist, as mentioned in the previous point.

As one can see, a more secure way would be to invest in something that regularly outpaces inflation (like stocks or bonds). The best way (especially if you can control the time travelling), is to make numerous stops, investing in securities that have very high short-term returns (for example, a stock that jumps 20% in value in one day, but overall has average growth), and continually reinvesting the returns. This removes most of the problems above, but may get you arrested for insider trading.

To avoid such hassle, one could be tempted to instead use time travel to gather collectibles before the majority are destroyed or lost. E.g., a 1928 $500 or $1,000 bill is still legal tender today, although worth much more than its face value to collectors. However, this scheme opens up a whole new can of worms in terms of authentication and ensuring your actions don't eliminate its future worth, not to mention you ought to leave the currency in a safe place then travel back separate from it and retrieve it - trying to sell a 1928 bill in 2020 that has not obviously aged 92 years will make collectors suspect the bill is counterfeit, even though it isn't. The bill will seem too new. Alternatively, a prospective time-traveler could get around the currency problem by using their seed money to purchase non-currency valuables, like jewels or precious metals, and then sell those at your investment-point to get chronologically appropriate tender. But watch out that they aren't Worthless Yellow Rocks in the future.

And of course, if any of these tactics are indeed possible, you probably won't be the only one to notice this. Hordes of time-travelers attempting to manipulate currency is sure to result in the eventual destruction of the economy (or the time stream). Time-travel responsibly, folks.

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Examples:

Anime and Manga

• In Doraemon, Nobita has Doraemon do this in an attempt to get a better allowance; though he does earn a buttload of interest, the bills are in future currency, so it only nets him a modest increase when it gets exchanged for present day bills.
• In A Simple Survey, one of the short films is a 20 Minutes into the Future setting where natural resources have been largely depleted. To compensate, scientists created a "time lodes", a limited means of time travel which allow small changes to the past. Using time lodes, critical resources which would be squandered in the past can be preserved and then recovered in the present.
• In a Tenchi Muyo! 4koma, Kiyone Makibi attempts to do this after the time traveling adventures of The Movie.

Comic Books

• Mystery in Space #12 "The Richest Man on 9 Planets". Sam Drake invents a suspended animation drug. After bank-depositing the single dollar he has left after paying his bills, he goes to sleep for a thousand years. Waking up in his miraculously still-intact basement in clothes that are still in perfect condition, he goes to the bank and retrieves his now $250,000 balance. Worried about changing monetary values, Sam tells the bank manager to invest his money in gold and goes to sleep for another thousand years, only to wake up in a world where gold is now common due to a cosmic accident.
• There's a variation in a recent Spirou and Fantasio story where the villain goes back to the nineteenth century to buy houses in the Marais quarter in Paris, then a common slum, now the most expensive part of the city.
• Léonard le Génie: Leonardo tries the invest-wait a day-go back trick once, but gets arrested for insider trading.
• A Disney comic had the Beagle Brothers (and their mom) travel back in time to take advantage of how much cheaper everything was then... and paying with present-day money. Naturally they get caught and accused of forgery, as all their bills have wrong yearmarks.
  • Another Disney comic has Donald Duck trying something similar. Scrooge tells him that he bought all properties in Duckburg and thus now owns most of the city. Before he can finish his story Donald gets an idea and runs away. Donald then buys old money from collectors, is sent into past by Gyro and buys all properties before Scrooge does so. He then returns back to the future, but instead of him being the owner of town, Scrooge still rules. Donald goes back to his uncle and asks him to tell the whole story. Scrooge says that someone had bought all properties, but then disappeared. So when the properties fell under compulsory auction to cover unpaid taxes Scrooge bought them all.
• A comic story had Pinky and the Brain planning to use a time machine to exploit the trope. They'd open a savings account in present time and then go to the future to collect their winnings. Their first obstacle was finding a bank that agreed to start a savings account with 37 cents. After they finally found one and opened their account, the bank was robbed and they went back in time to prevent their past selves from leaving their money there in the first place. Brain's worries about Never the Selves Shall Meet was justified as somehow it changed the world to have it ruled by ostriches.
• MAD made fun of the naive interest idea with a three-frame comic where an early-20th century father gives his son $10,000 and admonishes him to put it in the bank (as opposed to the son's idea of frivolously buying a new car), the son passing on the money (now $67,000) to his son with the same admonition, and the grandson passing on a full $100,000 to his son. The great-grandson remarks that a hundred grand is roughly the same money as ten was in his granddad's day... whereas if granddad had bought a Rolls Royce like he wanted, he'd now have an antique car worth $250,000.
• One sci-fi story detailed a man from a future where time-travel technology was common decided to head into the past to sell some cheap Martian diamonds then invest the money and move forward a hundred years to enjoy the wealth (while still living in what would be his past). Unfortunately he ignores the warning of the time-agent that tried to stop him and steals her device so she can't stop him only to arrive in a desolate future as all of humanity except the time agent (now a decrepit old woman) had died off due to the Martian Flu that the gems spread. Worse since he wiped out the future he destroyed all time travel technology making it impossible for him to undo things (and ends with her cackling her head off as she runs off as she'd fought to keep alive just to greet him and give him that bit of sniping when he returned).

Film

• This is invoked by Idiocracy's Joe to convince Frito to lead him to the time machine. Frito doesn't quite understand how it works, so he thinks he'll get the money even if he leads Joe to a fake "time machine" that's actually an amusement park ride.
• Timecop has time villains trying to buy Wall Street stock on the day of the 1929 crash, and cheap Hollywood land back when it was only worth a few cents an acre.
• A scene in Back to the Future Part II strongly implies Doc Brown engages in this. Marty needs some money from the timeline they're in, and Doc opens a briefcase with neatly arranged stacks of bills of various colors and sizes.
  • The comic books show how Doc got some of his money by traveling back to 1938, buying several copies of Action Comics #1 (the first appearance of Superman), then going to 2015 and selling them at auction for millions.
• In Time Chasers (spoofed on Mystery Science Theater 3000), the Corrupt Corporate Executive's wormy assistant points this out to the protagonist, who is showing off his working time machine. Of course, all our hero uses it for is taking his Love Interest on a date to the 1950s. Note that the entire conflict of the plot is kicked off because the Hero needs money and sells his invention to a Corrupt Corporate Executive.
• Averted in Vanilla Sky, where Tom Cruise's rich character is revealed to be flat broke by the time he's unfrozen 150 years later.
• Happens at the end of Hot Tub Time Machine, when Lou decides to stay in the past and is seen as a billionaire when everyone else returns to the present, having used his knowledge of the events in between.
• In The Final Countdown (1980), Lasky's (Martin Sheen) reclusive employer, a Mr. Tideman, has sent him as civilian contractor oversight for the recently-commissioned USS Nimitz, which, at the time of filming in 1979, had indeed recently been placed into service. After the events, in which the Nimitz mysteriously comes back to its then-present day, having been about to wipe out the first attack wave of the Japanese task force about to attack Pearl Harbor, and then, presumably, sink the six IJN carriers if not the entire Task Force, rendering the entire Pacific War moot, and being 'frustrated' (and likely also relieved) in the effort, comes back to an unenviable de-briefing. The only survivor of the attack on the boat that killed Sen. Chapman and all others aboard, including his lovely assistant, Laurel Scott (Ali McGraw) is the dog, Charlie, whom, as Lasky leads it down the gangplank, recognizes who's in the Limousine on the dock and runs into it, where a familiar woman's voice greets him by name. Lasky looks into the limo and recognizes a now-aged CDR Owen and Laurel, aka Mr. and Mrs. Tideman, who invite him into their car for a "long talk". As Laurel, after the helo is destroyed by Chapman's discharge of the flare pistol, having examined the provisions left behind with the '1979' dating, knowing that Owen is from the future, likely realized that she can take up a new identity with him. Obviously Owen had informed her of the changes in societal 'roles' for women. Of course, since Owen knows of events from 1941 to 1980, and likely has an extensive background already in Naval Engineering, he'd well be in a position to invest 'presciently', as well as "invent" some things here and there...
• In "Flykten till Framtiden", a man from 1973 travels to 2016 where his fatal heart condition can be cured, but he needs a small fortune for it (because he lacks a present-day identity and isn't in the system). With some help from his new 2016 friend, he purchases old decommissioned money, then brings it back so his old 1973 friend can buy houses that will become worth a fortune, and eventually use that to pay for the procedure.

Literature

• The Hitchhiker's Guide to the Galaxy Trilogy
  • Paying for a meal at "Millyways", The Restaurant at the End of the Universe, is made easy this way:
    All you have to do is deposit one penny in a savings account in your own era, and when you arrive at the End of Time the operation of compound interest means that the fabulous cost of your meal has been paid for. This, many claim, is not merely impossible but clearly insane...
    • The TV version of this explanation was illustrated with a cartoon showing a coin turning into a growing stack of coins, then bigger coins, then banknotes, gold bars and finally a plate of egg and chips.
  • Of course this has some interesting Fridge Logic because what do the people who were born within a few hundred years of the end of the universe do to pay for their meal?
• In "John Jones's Dollar" by Harry Stephen Keeler, a man deposits a dollar in a bank, stipulating that it and its accumulated interest are to be paid to "no other person than [his] fortieth descendant ... along the oldest child of each of the generations which would constitute his posterity". By the time the fortieth generation rolls around, the payout is greater than the total value of the combined holdings of the entire human race. And then the 39th descendant dies childless, with the result that John Jones' estate is absorbed into the State Treasury due to being intestate, nobody owns anything, and humanity is forced to become a communist utopia. Which is of course absurd on multiple counts, but then this is Harry Stephen Keeler.
• In H. G. Wells's When the Sleeper Wakes the protagonist, after sleeping for 200 years, wakes to find his fortune has accumulated to the point where he owns more than half the world. The trustees of his estate are the world's rulers. He becomes the figurehead for an opposition party that wants to take control, but once they have, realises they're no better than the first lot. Despite his wealth there isn't a lot he can do to make things better, since he's just one man and doesn't understand the world around him very well.
  • The Sleeper's funds weren't all just interest. One of the Sleeper's relatives as well as the man he fell asleep at became financially successful, and both chose to have the Sleeper inherit them. (The trustees of the estate are also portrayed as extremely aggressive businessmen, and the Sleeper's wealth owes at least as much to their finaglings as to the effects of compound interest.)
• Mentioned (thus becoming an Ur-Example) by a friend of the Time Traveler in The Time Machine. The Writer shoots this idea down by pointing out that the investor might arrive to find that the future society has gone communist and abolished money.
• The German novel Eine Billion Dollar (that's a trillion dollars in English), by Andreas Eschbach, has this trope as a premise: John Fontanelli inherits the fortune, originally just 300 florins, which his ancestor in the 16th century left for him, along with the prophecy that the heir will give mankind its lost future back.
• In "The Price of Oranges", a short story by Nancy Kress, an elderly man discovers a time corridor, and uses it to bring back fine cigars and fur coats bought 'cheaply' in 1937. It never occurs to him to buy gold certificates which will be worth a fortune now, but as the story shows he's well-meaning, but not very bright.
• Robert A. Heinlein:
  • Time Enough for Love provides the page quote as one of the aphorisms from Lazarus Long's notebooks.
  • Subverted by another Heinlein novel, The Door into Summer where the protagonist is put into cold sleep for 30 years and wakes up penniless due to the company managing his finances having gone bankrupt. The second time he cold sleeps, after having gone 30 years back into the past, he arranges for a better financial adviser and awakes to significant profits.
• In the Hyperion Cantos by Dan Simmons it's mentioned that one character (Martin Silenus) was put in suspended animation by his parents to pay off the family debt. He wakes up to find that all the accounts and debts have been frozen and then dissolved into the galactic economy, and he has to work as a common laborer.
• Averted by the rich villain's plan in The Anubis Gates by Tim Powers. Scheming to travel into the past and invest his wealth there, he also intends to become immortal and watch over his investment, taking full advantage of his economic foresight, rather than trust in compound interest alone.
• In the Ender's Game universe, Andrew "Ender" Wiggin gains quite a bit of money by moving from star system to star system at relativistic speeds. After some careful managing and over a thousand years of travel his account is sufficient to buy a planet. It should be noted that the only reason it works for Ender (and his sister Valentine) is that he has a sentient AI operating in real time keeping track of his investments. His money isn't just sitting in an account gathering interest, it's actively and intelligently being invested even while he's in relativistic travel. Probably doesn't hurt that he started with an ungodly amount of seed money, being the acknowledged savior of the human race and having been paid accordingly by a grateful world populace.
• In The Belgariad, Polgara does this the old-fashioned way. She puts a trustworthy person in charge of investing the token rents for land in her former duchy ... and then lives a couple thousand years. By this point, she could probably buy herself a kingdom if she felt like it, and may be one of the richest if not the richest person in the world. Too bad she has absolutely no interest in money. This may also not be an example, because the money isn't invested; it's simply the accumulation of small rents over the course of millennia. Her case is also aided by two things:
  • A severe case of Medieval Stasis, which is discussed and speculated to have been caused by the division between the two Prophecies, which prevents history from moving forward until the division is resolved, with the same events repeating over and over again, with only the fine details and the individuals involved changing - and even then, not by much.
  • The fact that the tense relations with the Angarak nations prevent their massive deposits of red-gold (which in the first series is shown as being The Corruption, used as a subversion tactic - since ordinary red-gold is later shown not having this effect, it's implied that the Grolims enchant it to have this effect) playing a part in the Western economy.
• Used by interstellar travelers in Stephen Baxter's Manifold: Space, who are frozen in time while traveling through the portal network. It works at first, but laws are eventually passed and assets seized, leaving the travelers flat broke when they return.
• Vernor Vinge's Marooned in Realtime begins with a 'colony' consisting of all the people that were in stasis during the 'singularity' that saw everyone else on Earth vanish in some unknown way. A pair of brothers are two of the travellers who were in stasis attempting just such a plan.
• Clifford Simak's Why Call them Back From Heaven? is a variation: "Give us all your money, and we'll resurrect you in distant future when we'll invent time-travelling". That means "never", because time-travelling is proved impossible.
  • Another story plays the "anabiosis + interest money" scheme completely straight.
• In The Dark Tower series, Eddie comes up with a plan to outmaneuver the Sombra Corporation's plot against the rose, by investing Odetta's capital from Holmes Dental in Microsoft and other up-and-coming businesses in 1977. Given such financial guidance, he predicts their Tet Corporation will one day be able to buy North Central Positronics out from under the bad guys by cashing in the investments in 1987.
• Subverted in The Forever War, and hard. The soldiers get quadruple pay for being away in space in a combat zone for the equivalent of twenty years. But by the time the soldiers get back to Earth from their first tour of duty, their money is worthless due to hyperinflation and chronic shortages caused by the war and a world-wide famine. And the size of their compounded pay puts them in a 92% tax bracket. At the end of the novel, most other humans are clones who do not use money, so all of their combat pay is worthless. At one point, William, the narrator, buys a hugely expensive bottle of ancient French brandy to share with his officers, reasoning that investing the money was the alternative. ^note Elsewhere, there are still colonies where people are normal, and presumably still use money.
• It's given an offhand mention in The Dresden Files a couple times. But it's never just sitting around collecting interest, as the White Council has several staff members (pun not intended) that are tasked with managing the Council's finances.
  • Also part of the reason why Madeline Raith doesn't firebomb Harry's house looking for Morgan, as she doesn't realize that Harry hasn't had a chance to shore up his accounts yet. Also, she's just a Rich Bitch that's Rich in Dollars, Poor in Sense.
• In Tom Holt's Flying Dutch, the legendary Flying Dutchman had a life insurance policy which still paid off several centuries later-so much so that to cash it in would bankrupt the entire world economy (The insurance company figured that since most people in that era died before seeing 60, offering 50% compound interest for every year someone lives past 75 would cost them nothing. Then Vanderdecker ended up living to be more than 500).
• In "Compounded Interest", a 1956 short story by Mack Reynolds a time traveler places a small sum at 10% in a bank in medieval Venice and renews the contract every 100 years. By 1960s the sum exceeds the price of everything in the world several times over. Then he comes to the organization servicing The Contract and starts gradually withdrawing money. What for? To build a time machine to go to medieval Venice to place the money. You see, when The Contract employees concluded the scheme was started by a time traveler, they consulted with several famous physicists, including him, about the possibility of time travel. He told them time travel was impossible, but later figured that it was possible, only R&D would be prohibitively expensive. Thus he came with the plan and started withdrawing money before he deposited anything.
• In David Weber's Honor Harrington series, this was the plan of the founder of Manticore. After his investment group bought the rights to the planet and system, he put what was left into a trust. Since this was prior to the invention of safe FTL travel, the colonists had to be a Human Popsicle, and travel on a Sleeper Ship. When the colonists finally arrived and were unfrozen around six hundred years later, the trust had grown considerably.
  • Additionally technology had advanced to the point that FTL travel was now safe so the managers of the trust were able to use some of the money to send a few ships to the colony site to make sure that everything was okay before the original colonists arrived.
• A non-time-traveler example in The Lost Fleet. At the end of the main series, Captain John Geary, who has spent the last 100 years as a Human Popsicle, has finally returned the titular fleet to The Alliance space. He plans to take some R&R. His former lover Victoria Rione tells him that, with his accumulated pay, he should be pretty well off. Geary informs her that the fleet bureaucracy has determined that survival sleep did not as count being on duty, specifically to avoid paying officers and sailors for the possible years and decades spent on ice (a few less extreme examples had happened earlier in the war); therefore, his pay was suspended when he was declared MIA. His accounts were frozen as well, and then presumably closed and the funds distributed to his next-of-kin when he was declared Legally Dead. Thus, the only pay he has now is only from the moment he was awakened. Luckily, the same rules don't apply to seniority, otherwise he would've never been given command of the fleet.
• Another unlucky Human Popsicle in Larry Niven's A World Out of Time found out the hard way that the courts of his time ruled those like him could not own property and thus the assets he set up for himself were long gone.
• The first real mission of the D.O.D.O in The Rise and Fall of D.O.D.O. is to secure funding for themselves via stashing away a pristine copy of the 1640 Bay Psalm Book. Of course there were complications.
• Doctor Who Expanded Universe:
  • The Doctor himself admits to doing this in the Doctor Who Missing Adventures novel The Crystal Bucephalus. He explains that to avoid drawing too much attention, he occasionally has to invest huge sums in doomed business ventures, such as the time-travelling restaurant of the title (and the British film industry).
  • In the New Series Adventures novel At Childhood's End, Dorothy "Ace" McShane reveals that the initial funding for A Charitable Earth came from nicking fifty quid from the Doctor's wallet during World War II, and depositing it in a bank that was still around in her own time.

Live-Action TV

• The titular character of Angel is notable for not attempting this. Many vampires and demons use their long lifespans and considerable powers to form and maintain successful businesses. By contrast, Angel has to charge the people he helps because, as Cordelia points out, he never bothered to make any investments over a 200-year life. Apparently when he was the evil vampire Angelus, if he wanted something he'd just kill the owner and take it, a pattern of behaviour that doesn't encourage a creature of the night to put aside for a sunny day.
• Discussed briefly in an episode of Being Human: when Vegetarian Vampire Hal reveals that he has little to no money, Tom asks why he didn't just get a bank account, because being immortal and everything even if there had been periods of massive inflation or something then he'd still have a small fortune.
• Parodied in Childrens Hospital, when one character travels back to The '40s, he makes a Long List of companies to invest in, then puts it in a desk, where it stays for the next sixty years.
• Doctor Who:
  • In The Time Meddler, the eponymous meddler claims to have done this. Though given what had already been shown in previous serials, he would have had to withdraw his money in a year when Earth was a post-apocalyptic wasteland ruled by the Daleks.
  • A series of trading cards from the mid-90s explained the difference between the Meddling Monk and the Master with this: The Monk would use a complex time-travel gambit to accrue his fortune, but the Master would walk into the bank, murder the staff, and walk out with an even bigger fortune!
• Eureka: In "I'll Be Seeing You", during a trip to 1947 Dr. Trevor Grant takes the opportunity to buy 1 000 shares in Johnson & Johnson, which on returning to 2010 makes him extremely wealthy.
• Used by the Victorian-era villains in the CBBC series The Ghost Hunter, once Time Travel was introduced as a plot point.
• In Goodnight Sweetheart, this gets tried using the portal that connects contemporary London with war time London, but the company that they invest in split in the 50s and, without any contact from the investors, the bank puts the shares in the half of the company that folded.
  • A case of research failure: in real life he would have ended up owning shares in both spin-offs.
• A non-time travel example: an episode of the Highlander tv series shows Duncan taking advantage of his immortality with this strategy, mentioning that Zürich, Switzerland is where all immortals keep their money.. Thanks to his "great-great grandfather" depositing 10,000 francs, his account holds over a million. Humorously, one time when he tried this the bank was robbed while he was in the middle of cashing out the account. So much for that idea...
• In a Red Dwarf episode, it is revealed that Dave left £17.50 in his bank account on Earth. Three million years have passed, and he now owns 98% of the world's wealth. He also left a sausage out on his table which went mouldy; now the mould covers seven-eights of the surface of the Earth. Furthermore, he left the lightbulb in his bathroom, racking up a gigantic debt to the local utility company, which has now become the ruling faction on Earth and whose battle fleet is rapidly approaching in an Attempt To Collect. It turns out to be a joke by Holly.
  • Mentioned in the American version. Lister's first words after being informed that he's been in suspended animation for almost three million years involve exclaiming that his baseball cards must be worth a fortune.
  • In the original version he also laments that he has an unreturned library book.
• In an episode of Sabrina the Teenage Witch, Sabrina's aunts explain how they got rich: junk. When you live hundreds of years old, it's easy to buy worthless commercial junk made by the hundreds of thousands of units and put it away for a few hundred years until age and scarcity turn them into priceless antiques. They add that the Mickey Mouse plates they just bought will be worth millions in a few centuries.
• Forms a Brick Joke in the Stargate SG-1 episode "1969". After SG-1 is sent back in time to the eponymous year courtesy of an interaction between the stargate and a solar flare, Jack borrows some cash from the future General Hammond, then a lieutenant, and promises to pay him back with interest. When they get back to 1999, Hammond tells Jack he owes him $539.50, including interest.
• Subverted in Star Trek: The Next Generation. A businessman who was cryogenically frozen during the 21st century arranged for a firm to manage his account, expecting to awake to a great profit. As it turns out, a third World War and conversion to a currency-less economy left any remnants of his accounts worthless. While he's upset at this, he doesn't realize that he can get anything he wants just by talking to a replicator. In an Expanded Universe novel, he becomes the Federation ambassador to the Ferengi, given his rather unique skillset and understanding of the capitalist mind.
• Supernatural.
  • When Sam and Dean travel back to 1978 in "The Song Remains The Same", Dean off-handedly suggests they invest in some Microsoft stock while they're at it. Sam says they may have to if they can't find a way back.
  • In "Time and Time", Chronos raises ready cash by placing bets on horses, using time travel to get the results. Dean traces him through his bookie.
• Played with in an episode of The Twilight Zone. Four thieves steal gold and freeze themselves for a hundred years, thinking they will be able to claim their riches after everyone has forgotten about the crime. Turns out that the crime has been forgotten, but in the future gold can be cheaply manufactured and is therefore worthless. Their intent is different (hoping to avoid interest rather than earn it) but the result is the same.

Tabletop Games

• Shadowrun supplement Portfolio of a Dragon: Dunkelzahn's Secrets. One provision of Dunkelzahn's will stated:
  To Art Dankwalther, I leave the sum of 34,586,224,739.58 in UCAS dollars. According to my calculations and accounting for conversion of the original currency, inflation, and 1 percent interest per annum, this settles my debt to your ancestor for the gold piece he kindly lent me for the last meal we shared.

Video Games

• The Time Travel based RTS game Achron has a variant of this known as 'Retconomy'. One of the playable species creates harvesters by morphing one of their basic units. These basic units can be built and paid for in the future and then sent into the past where they become harvesters and begin gathering resources. The end result is that the player will have gathered more resources in a shorter amount of... er... time than a player that had not used time travel.
• It's possible to pull this trick off in Animal Crossing. Deposit a reasonable sum of Bells in the bank. "Time travel" by setting the system's clock as far forward as it will go. Go to bank and check sum. Profit! Then you can travel back in time and safely keep your vast fortune. The downside? Your town will become a depopulated, weed-ridden wasteland, of course. You can avoid weeds if you enact the Beautiful ordinance in Animal Crossing: New Leaf and Animal Crossing: New Horizons, though your villagers will still move away; version 1.2.0 of New Horizons also nerfed the interest rate from 0.5% to 0.05%, meaning that only 9,999 Bells at most can be delivered in your bank account, making this method completely unreliable for profit.
• A strange case of banking and time travel is possible in The Legend of Zelda: Majora's Mask. Link has the ability to rewind time 72 hours before a certain point in-game time, and predictably, when he rewinds time he loses all of the money he accumulated during that 3-day period. Fortunately for Link, the hub city's bank is apparently temporally insured, since the banker stamps Link's account balance on his head, and this stamp never fades or disappears with the rewinding of time. Realistically, this should mean the complete destabilization of the city's economy, since the money deposited at the end of the 3-day cycle technically does not exist at the beginning of the cycle, but most people are probably more worried about the moon falling out of orbit than they are about time-travel based banking scams.
• Can be easily performed in Fable II right after the main story begins. Rent out your caravan for a measly few gold, then set your clock forward a few decades. Use that money to buy more property, repeat, and you can own all of Albion the moment you lay eyes on it.

Webcomics

• Dave Strider of Homestuck has the LOHAC Stock Exchange in his back pocket thanks to this trope.
• Spinnerette has a time-traveling Benjamin Franklin use this as a means of obtaining start-up capital for the modern-day superhero support organization he runs in the present day. Interestingly, it's stated that the money wasn't that much, only enough to get things started, and most money comes from merchandizing deals.
• In Casey and Andy, Jenn always carry a small supply of gemstones in case she ends up travelling through time or dimensions (which is very, very often for her) because they are almost always valuable and can be sold for legal tender with minimum hassle. Of course, the main reason she carries jewels is she is a professional jewel thief.
• In 21st Century Fox there was a Chinese space station full of dissidents who wanted to freeze themselves at an "abandoned" North Korean moonbase for 500 years in the hopes that China would have more women then, and use their accrued interest to live like emperors. After Jack escapes from them he hacks their bank accounts and donates their money.
• In one Saturday Morning Breakfast Cereal strip a guy puts all his money in a 10,000 year CD, then freezes himself intending to be the richest man in the world when he's thawed. Only to discover that the world has adopted a moneyless post-scarcity economy.

Web Original

• Dr. Steve tries a variant of this in The Adventures of Dr. Floyd. While he's always got a time machine and is trying to sell various things on ebay for profit, one time he simply bought 100 copies of Action Comics #1 and tried to sell them when he got back to the future. The problem is he neglected to seal them properly and they disintegrated!
• The American Dream Film - Pile wonders if having more money means that you can be immune to all the taxation-fueled propaganda that Hartman has been feeding him. Hartman thoroughly crushes this theory by testing it out with this trope, using Michael J. Fox's time machine to buy an entire house in 1955 and then sell it for millions in the future - only for taxes AND the taxation on taxes to manifest in the form of IRS agents screaming "grab grab grab", leaving them with technically (after inflation) less money than what they used to buy the house.
• A variant occurs in the Strong Bad Email "space program", where Strong Bad and The Cheat plan to take $15.00 into space, which, according to their 'vague understanding of the Theory of Relativity' will become $1 million after they return. It turns out that they never even get a chance to see this plan fail, as they spent the money on a sound effects CD before takeoff.

Western Animation

• An odd variant in Back to the Future: The Animated Series: Jules and Verne travel to 2091 and have to take a cab, but find out the cab fare is very high. The only money they have is a quarter; however, it turns out that a 1983 quarter is a rare and expensive collector's item by that point in time. The cab driver skips away in glee at his new fortune.
• Inverted in The Flintstones: Fred borrows 4 dollars on his paycheck so he can have a long weekend with Wilma and the Rubbles. Thanks to the Great Gazoo, they get sent to a very Jetson-like future. While he's in the future, he visits his employer's descendant, and discovers that he owes his company 23 million dollars.
• In the Futurama episode "A Fishful of Dollars", Fry needed 50 cents to pay Bender's bail and realized he still had just under a dollar in the bank. He goes to the bank for the first time in a millennium and discovers that he's rich beyond imagination. Unforunately, he falls for an elaborate scheme to steal his money after he obtains the world's last can of anchovies, which would then be used to buy them off him. He ends the episode as broke as before.
• The Stable Time Loop plan on Gargoyles that helped make Xanatos part of the Fiction 500 comes close to this trope. Xanatos went back in time and earned a practically worthless coin that he then had the Illuminati Society deliver to a David Xanatos 1,000 years later... when it was worth 20 grand. The rest was investments.
  • Which was also part of his lesser plan to prove to his father that he was a Self-Made Man. His father is unimpressed, and gives him a penny as a wedding present. Not worth much now, but might be in 1,000 years “and it seems to be all you care about”.
• Double Subversion on South Park, where the money saved this way was almost worthless in the future due to inflation, but it was still better then the grinding poverty most people suffered from.

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