Solo proof-of-work mining does not satisfy the Howey Test criteria for securities transactions because individual miners do not rely on others' managerial efforts for profits, according to the SEC’s statement that proof-of-work mining isn't a security

Quotes that support claims

A miner’s Self (or Solo) Mining is not undertaken with a reasonable expectation of profits to be derived from the entrepreneurial or managerial efforts of others.

The statement, published by the SEC’s Division of Corporation Finance, declared that both solo proof-of-work crypto mining and pooled proof-of-work crypto mining do not meet the definition of a securities transaction under the Howey Test — the legal framework used to determine whether a transaction represents an investment contract — because they are “not undertaken with a reasonable expectation of profits to be derived from the entrepreneurial or managerial efforts of others.”