(Reuters) - The U.S. Securities and Exchange Commission (SEC) has delayed a decision on whether to approve applications for spot bitcoin exchange-traded funds (ETF) from Invesco, WisdomTree and Valkyrie, a filing by the regulator showed on Thursday.

The SEC has pushed back the decision dates for the three proposals by several weeks to mid-October, but could potentially delay further. It was previously due to make a decision by next week.

The delay comes just two days after a federal appeals court ruled on Tuesday that the SEC was wrong to reject an application from Grayscale Investments to create a spot bitcoin ETF. A three-judge panel of the District of Columbia Court of Appeals in Washington said the regulator failed to fully explain its reasoning when denying Grayscale's product.

The ruling requires the SEC to review Grayscale's application, meaning there is no certainty it will reach a different conclusion and green-light the product. The regulatory agency, which on Tuesday said it was studying the ruling, could appeal.

The SEC has in recent years rejected dozens of applications for spot bitcoin ETFs, publicly traded investment vehicles that directly track bitcoin prices, citing inadequate levels of trading surveillance that could leave the underlying spot market subject to fraud and manipulation.

In June, BlackRock, the world's biggest asset manager, also filed for a spot bitcoin ETF, a move that many viewed as a game-changer for the industry which and boosted the price of bitcoin.

(Reporting by Hannah Lang in Washington; Editing by Matthew Lewis)