Show HN: Double – Design and invest in your own stock index

178 points by jjmaxwell4 ↗ HN
Hey everyone, we’re JJ and Mark from Double (https://double.finance). Over the past few months we’ve been working on an investing app that lets anyone design and invest in their own stock index.

Start by picking one or more strategies. You can find 20+ starting points in Double that vary from direct index versions of classic ETFs (like SPY) to strategies focused on specific industries, market trends, or themes (like YC public companies). You can also easily build your own grouping of stocks, and tilt your strategy towards or away from certain stocks or sectors.

Once you’ve chosen your portfolio, we run a daily portfolio optimization to determine what trades to make, which considers taxes, trading costs, drift and holding costs[1]. If your account is sufficiently diversified, we enable Tax Loss Harvesting as well to capture losses that can help offset capital gains[2]. Finally you can move between strategies either all at once or over time[3].

JJ started work on this after selling his last company, making some money, and growing really frustrated at the quality of the portfolio tools available to retail investors. Financial advisors have tools for direct indexing, tax loss harvesting and dollar cost averaging, but they generally charge upwards of 1% a year in AUM fees. Things like Parametric[4] and Canvas[5] have succeeded, but are only accessible through advisors. We wanted to build these kinda advanced portfolio tools for ourselves without any AUM fees.

Some common use cases we’ve found are diversifying away from a large RSU position or migrating between risk on and risk off strategies over time. You can also easily allocate a percent of your portfolio to specific baskets of stocks.

Let us know what you think! Feel free to email us at founders@double.finance as well

[1] More info about our optimizer here https://help.double.finance/en/articles/9718142-portfolio-op...

[2] More info about out direct indexing tax loss harvesting here https://help.double.finance/en/articles/9718959-direct-index...

[3] More info about out dollar cost averaging here https://help.double.finance/en/articles/9718389-dollar-cost-...

[4] https://www.parametricportfolio.com/

[5] https://canvas.osam.com/

102 comments

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Very excited to try this out.
I'm JJ's brother and an investor in Double so I'm a little bit biased but I believe reducing/eliminating AUM fees is a huge net positive for the world. The performance drag over long term that money managers charge is a tax on people's retirement savings. What Vanguard/Bogle did with Index funds was massive, and I think Double can be this generation's Vanguard. Professional and powerful money management tools with rock bottom/no AUM fees is a massive opportunity. Congratulations on the launch JJ and Mark!
If Double doesn't charge management fees nor commissions for trades, how does it get paid? Flat fee or payment for order flow?
> Double is only available to US residents.

I would have loved to see that message on the Sign Up page before I enter my email address.

Thanks for the feedback, we will try and make this more clear for Non US IPs.
US residents != US IPs
Indeed, some US residents do travel outside the country occasionally.
Oh for sure, we just plan on showing a banner if the IP is non US. You can still fill out the application if your IP is non US.
And non-US residents occasionally use US IPs.
US Residents? What about US Citizens living abroad?
No unfortunately we do not currently support US citizens residing abroad. There are a few restrictions on opening an account, namely: must be 18 years old or older, has a U.S. social security number, a permanent U.S. residential address and phone number, and currently resides in the U.S.

Feel free to check back here for updates https://help.double.finance/en/articles/9457976-who-can-open...

Congrats! How does this perform against VOO if you take tax harvesting into account?
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This looks very cool - but I'm hesitant to sign up without knowing how you make money. Is it PFOF? Transaction fees? Flat fee?
Typically an ETF takes a management fee of 0.1-0.5% of assets per year. I expect this build-your-own-ETF to do the same, with fees on the higher side.
They specifically say no AUM fee.
This can change on a whim and you have no security against it.

For example, Guideline. They charged fixed fees on employer 401k accounts , until they didn't earlier this year.

We eventually will charge a monthly fee as described in our Form CRS, but we are waiving this fee for the time being. Eventually we plan on making money like Robinhood, M1 and other commission free trading pioneers. This means PFOF, Stock Lending, line of credit and other potential revenue sources. We are not currently offering these products. Please see our website for more details and our disclosures: https://double.finance
What will be the structure of that upcoming monthly fee?

I'm not interested in investing my time and money getting onboarded with a service unless I know the long-term fees are going to be amenable. If it said something like, "$15/mo and free for the first year" I would be on board.

This is great, exactly what I was looking for, but how do I know I can trust you? I'm a bit hesitant to wire large amounts of money to a startup.

Also, how do you make money?

Why trust us?

1. We're working with Apex Clearing, a large US Custodian with more than $100B of assets. Your account is in your name there.

2. We're well funded and backed by reputable investors (YC, Matrix, Youtube Cofounder, and many others).

3. We are registered with the SEC as an registered investment advisor.

4. I personally am in the process of transferring nearly my entire net worth onto the platform.

We eventually will charge a monthly fee as described in our Form CRS, but we are waiving this fee for the time being. Eventually we plan on making money eventually like Robinhood, M1 and other commission free trading pioneers. This means PFOF, Stock Lending, line of credit, etc. We are not currently offering these products. Please see our website for more details and our disclosures: https://double.finance

Great answer, thank you.

Another question: do you guys support trading of fractional shares in these custom indexes? If so, what's the smallest supported share % (eg 1%, or 0.01%)?

Yes we support fractional shares!

The fraction of a stock you can buy is currently based on a dollar amount. In our case right now it's $5.10 per stock ($5 with $0.10 of room to allow for fluctuations in prices). We are looking to lower this over time though and as our daily trading volumes grows this should come down significantly.

Love 4.
I'd be wary about 4. I've worked at a fintech startup before where the founders boasted about how they had moved all their net worth onto the platform. Some time later over a casual chat and drinks, it turned out this was far from the truth. Don't just take people's word for it, I may be biased about startups now, but "trust but verify" is a good motto to go by.
Number 4 makes it sound like a scam to me.

"Don't worry bro, you can trust me" type of vibe.

PFOF is a deal breaker. If everyone but Fidelity is doing it thats a huge selling point for Fidelity. Go against the grain and do what is right for your customer if you want to have the net worth of people who care about their money and thus more trust than Robinhood.
Why would you care about PFOF as a retail investor? You're benefiting from it.
No you are not. Your orders are not sent to the best exchange execution possible but to market makers who pay kickbacks to your broker and give you a far worse deal with every single transaction. The cost of poor execution is much higher than a 2 dollar commission (which is what Fidelity shows). It also reduces market transparency.
> Your orders are not sent to the best exchange execution possible

Look up NBBO, that would be illegal. You're getting better execution as a retail trader thanks to PFOF.

I have tried several PFOF and regular brokers. The spreads end execution of PFOF where far worse.
IBKR, vanguard, and I think even Bank of America also don't do PFOF.
Are there plans to allow residents of other countries? (namely Canada in my case)
Unfortunately this is not on our immediate road map. Sorry about that. I'm Canadian myself and I really wish we could.
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Do you plan to offer subscription-based access to other users' indices?
At this time no but if you have a index or strategy you want to see on Double please email me at founders@double.finance
SV money and banking relationships don't prevent a total meltdown, as seen in the Andreessen Horowitz-backed Synapse saga with Evolve.

Assume there's just a 0.1% of a meltdown and you're better off sticking to Vanguard ETFs.

https://archive.is/G3cYF

This is cool. There is a lot of hesitation to move significant assets from my Charles Schwab brokerage account. That's going to be my main hurdle. I need to understand the safety, trust, trading mechanics, flexibility that I have with Charles Schwab, all of those things become very valuable when talking about high amounts for retirement purposes. I don't really know what you can do there to attract such clients? Will anyone move $5m from their top tier brokerage to Double yet?
"Will anyone move $5m from their top tier brokerage to Double yet?"

I have!

But I understand that yes this is a hard thing to get people to move and trust, safety and trading mechanics are incredibly important. We are trying to be as transparent as possible on all those factors. I would love for you to try us out with a smaller amount first to see observe all the mechanics before making a larger move. We support full and partial ACATS transfers of existing stock positions (meaning you don't have to sell anything).

>> There is a lot of hesitation to move significant assets from my Charles Schwab brokerage account.

I'm incredibly double-minded about this. M1 offers essentially the same service and they do it very well. I've compared M1 vs Fidelity Basket Portfolio (which also offers yet almost the same service.) Here are my takes

- M1 is easy to use (mostly, though same super-strange UX choices)

- M1 is a pleasure to use

- M1 doesnt fail on the main features

- M1 Baskets of Baskets gets complicated, but understandably so.

- Fidelity is better in some ways as it allows trading anytime, not just on specific windows as M1 does (this can also be a downside for itchy fingers)

- Fidelity Basket Portfolios is broken 30% of the time. Their OWN buy function fails any time they cannot get a quote for any 1 member of the portfolio

- Fidelity: It is absolutely a headscratcher how, in 2024, Fidelity can have trouble getting quotes for liquid public stocks during market hours (e.g., the other day, their buy of an entire pie failed because they could not get quotes for "DVY" which is highly liquid

- M1 fails absolutely miserably on back-office functionality. Selling losing lots is almost impossible without major Excel wizardry since the accounting info is held separately in APEX

- M1 fails dangerously on things they should never fail on -- for example setting beneficiaries has been a 4-month journey and still remains unresolved. If you dont have a will, get prepped for Probate! Worse, the failure is a silent failure as it suggests on the UI that beneficiaries are set. You get different answers from different people and each wants to help you but runs from "complex" issues (in M1's case, they are designed to have a single account, so their backend features fail if you have multiple accounts (e.g., a RothIRA and a non qualified account.)

The dangerous, infuriating, and befuddling experience with setting beneficiaries on M1 lead me to stick to the majors (Schwab, Fidelity) because at least I can rest assured they have the basics solidly figured out. It also makes me very hesitant to go to startups for this sort of stuff

> accounting info is held separately in APEX

So the good news is that M1 doesn't use apex for clearing anymore

The bad news is that... things got worse? After they swapped to doing clearing in house, they dropped like a month of incoming wires without reaching out at all, until I noticed on my monthly login. Turns out that they had changed the underlying wire instructions (makes sense), but sent an email saying that nothing would change on transfer instructions (not true).

Then the next month, they still dropped wires even with the correct instructions, because... ???? unknown reason. Again no contact, until I reached out and asked wtf. Third month, everything worked even though nothing was changed from the prior month.

So there's a reason why I won't put more than SIPC worth in M1 or any other new fintech. And yes, it's backend incompetence as the primary reason.

I'd love to earn your business.
The only thing I use M1 for is to automatically purchase a 60/40 split of VTI/VXUS with any available deposits, so if double can do that, then maybe I'll check it out. If y'all are gonna charge a monthly fee down the road though, it's probably not for me.
I'd love to understand why this feature/product requires an entire startup. I dont mean to be dismissive -- obviously it does, as shown by my experience with Fidelity Baskets given they cannot achieve it!

Also, I used FolioFN and ShareBuilder for years to do the same and they seem to have flopped despite having a compelling product. I'd love to understand why such an obvious feature/product with sound alignment to financial recommendations cant seem to do well in the marketplace!

Would you consider making the optimizer available as a standalone tool?

I've wanted a tool to do this - set a target portfolio and tell me what trades to make, taking into account transaction costs and index rebalances. I just want to buy some broad indexes so it would be great if I could buy VOO and VWRL and forget about it, but ETFs are tax-disadvantaged in my jurisdiction [0] so I tried to replicate them manually in spreadsheets. I would consider switching brokers to someone who offered this tool, though right now you're not available in my area.

[0] https://nationalpensionhelpline.ie/taxation/tax-on-investmen...

I'd love to make some of our tools available outside a brokerage relationship, but this isn't something that's on our roadmap right now. If you want to chat about how you might be able to do this more effectively yourself, please let me know - founders@double.finance
Been looking for something like this. Well done.
Several years ago, I worked at a company called Motif Investing that was conceptually similar this. It was marketed more as a "build your own ETF" kind of thing. You could assemble and weight up to 30 stocks in a "Motif" and manage it over time. We had some of the features you mention as well. I was happy with the product and enjoyed working their, but the business never really took off. I wish you the best in developing your company!
Thanks. I know of and have always respected Motif.

Would love to chat about any hard learned lessons along the way if you're up for it - founders@double.finance

It's what I want since I've been just DCA with recurring buys on Robinhood.

Let me know when you guys plan to hire.

In regards to making a "S&P - company/sector" portfolio, how can you compete with other ETF issuers? I feel like you wouldn't be able to get an expense ratio close enough to other large ETFs for the risk weighted return to overcome it. You can maintain a low expense ratio that down weights a sector by combining ETFs. But instead of having a high AUM to reduce churn, that expense is on me.
I'm a bit confused by your question, but we do not plan to charge any AUM fees.

By direct indexing you get a lot more flexibility to customize the index on a stock/sector/factor level.

Thanks for checking us out.

If I were to set up a customized S&P500 (with some tweaks) and over time companies leave and/or are added to the index. Will those changes be reflected in my custom S&P500? In the months or years in the future will it buy or sell these new currently unknown companies?
Yes we handle corporate actions and index additions or deletions and weight changes over time for you.

The guts of this get a bit complicated and I want to make a blog post about how we achieve this for adjustments.

Congratulations on the launch! Wishing you the best of luck.

Q: why only US residents? Other brokerages in the US take in non-US residents (in my case, not even a US person).

Can I acat into double?
Yes, we support ACATS. You can initiate these through the app under Transfer Funds.
Are you hiring?
Optimistically. If you're interested shoot me an email jmaxwell at double dot finance
love it! any plans to allow for sharing custom indexes with friends/family (or would that run into regulations)?
Yes we'd love to allow for sharing and we've got some ideas for that already.
Why not just buy the basket of stocks?
This gives you knobs to turn, which gives users shots of dopamine (at the cost of lower long run expected return) and helps retention.
FYI, on Chrome (Windows machine) your home page is missing the vertical scroll bar.
Very basic, maybe stupid question: If you're not changing your portfolio strategy or altering your weights, does this work by rebalancing your investment every so often, so that the % of total dollars you hold in an index continues to match the weights you set?

Like if a customer creates an index that's 50% AMD and 50% NVDA, and you put $100 in that index, does the customer have some underlying account that initially apportions $50 to each, and then if the next day their NVDA is worth $52 and their AMD is worth $48, the system will sell $2 worth of NVDA and buy $2 worth of AMD?

And if that's so, can you set target thresholds for when you want it to rebalance? Like, not until one stock deviates more than 10% from its ideal weight?

Not a stupid question at all.

Short answer for your simple scenario is yes it would rebalance. The longer answer is it depends on the output of our optimization engine.

Our optimizer tries it's best to make the portfolio better, taking into account drift, trading costs and taxes and potentially holding costs for etfs and a factor model for broad diverse portfolios. Wash sales also play a large part because by default we prevent any wash sales from taking place.

These objectives can compete against each other (tax harvesting is generally good but in your example requires selling AMD not buying it). We run an optimization to try and balance these and come up with trades that make the portfolio better. By default we rebalance if the optimizer thinks the portfolio will get better above a threshold we set.

We have the ability to rebalance based on naive weight drift as you discussed at the end of your comment - right now it's not enabled by default. We are hoping to add a setting so users can enabled the optimizer to only trade if x number of stocks have drifted more than y%.

Please check out this article to learn a bit more: https://help.double.finance/en/articles/9718142-portfolio-op...

Another stupid question. How much of that is your total portfolio?

More than 30%? Less than 30%?

Less than 30% means that you're still ok if double fails. More than 30% means you have a significant portion riding on it.

If you're worth 50 million, you can probably lose 5-15 million and still be okay...