The odds of a bitcoin ETF being approved dropped considerably in the last 48 hours, as the SEC has asked virtually every company that filed for a bitcoin ETF using bitcoin futures to withdraw their filings. That includes proposals from VanEck, First Trust, REX, ProShares and Direxion. Add those names to the Bitcoin Investment Trust that withdrew its filing recently after it looked unlikely it was going to get approved.What's left in the SEC's pipeline following the carnage? The Winklevoss Bitcoin ETF is still hanging on. The SEC denied its proposal last year, but says it's reconsidering. The Bitcoin Investment Trust still remains available trading OTC. I haven't heard any update on the GraniteShares Bitcoin ETF filing, but given that it planned on using bitcoin futures as well, it's safe to assume that it's either dead or will be soon.So, what's the SEC reasoning for wanting all the bitcoin ETF filings pulled? Liquidity and valuation. That's the indication given from the SEC when being asked to withdraw. The SEC has long had concerns about cryptocurrencies, but it was thought that the process for a bitcoin ETF approval would speed up once bitcoin futures were introduced. Since futures would be overseen by the SEC (and since many other ETFs already exist using futures contracts), it figured that this would give the SEC the degree of comfort it needed to see a product get approved.Turns out that the SEC's discomfort with cryptocurrencies is stronger than any comfort it might feel with the futures contracts. I originally thought at the beginning of the year that we'd see a bitcoin ETF get approved by the end of the first half of 2018. That seems very unlikely at this point, and it's unclear now when we'll ever see one. Interestingly, there's still a bitcoin ETF proposal from Evolve up in Canada. They've traditionally had a more relaxed regulatory environment, and could still give the OK for a fund yet.What do you think? Are you still interested in investing in bitcoin or other cryptocurrencies?