The SEC has again disapproved several proposals for a bitcoin ETF.

The latest rejection involves two ETFs filed by ProShares that would track bitcoin futures contracts, another from GraniteShares, and five leveraged and inverse ETFs from Direxion.

This follows on the heels of the SEC's rejection of the Winklevloss ETF in July that would have traded physical bitcoin.

Similar to its rejection of the Winklevoss ETF, the SEC expressed concern about fraud and manipulation of bitcoin markets. It said that NYSE Arca, which filed the ProShares application, had not met its requirement "that a national securities exchange's rules be designed to prevent fraudulent and manipulative acts and practices. Among other things, the Exchange has offered no record evidence to demonstrate that bitcoin futures markets are 'markets of significant size.'"