You are right. I indeed looked at the options for BTC futures, not the futures itself…
To correct my initial calculation (prices as of 30.09.21 08:23 - CME prices from 00:16 CT, not sure if they operate 24x5)
- BTC price (according to coinmarketcap): 43’629.36$
- BTV21 (BTC future Oct '21): 43’660$
- BTX21 (Nov '21): 43’620$
- BTZ21 (Dec '21): 43’920$
- BTF22 (Jan '21): 44’195$
- BTG22 (Feb '22): 44’390$
- BTH22 (Mar '22): 42’905$
- BTZ22 (Dec '22): 44’130$
Annual return (for BTG22): (44’390$ - 43’629.36$) * 100 / 43’629.36$ = 1.7434%
Doesn’t look like a proper return / risk deal to me. Not sure where you have the 8% annualized from, but the numbers above are from CME, which I personally would trust WAY more than Deribit. So if Deribit is offering you 8% annualized, there might be something fishy. Short summary: the market doesn’t expect high fluctuations in the next 6 months (as of right now).
Please note that I’m not saying this approach couldn’t work, but there needs to be way more volatility to increase the future prices for BTC.
You didn’t mention on which amount you made the 15% return from April to September, but it’s different if you invested 5k back then and made 15% vs. “investing” six figure amounts of borrowed money to invest in an unregulated cryptocurrency exchange.
As a last note: if you think it’s a good idea, you have made your due diligence, and you know about all the risks: go for it. We just wanted to show you that there might be some things you haven’t considered yet. You are responsible for your own decisions