Some coinbase transactions have locktime values set. One such recent example is:

  "txid": "5166cb509a5d786db33963a269ea08ff82a1c40d37d4fb828a394b0465cd5efd",
  "hash": "075ffc5116296983aaa8286b4fdbaac101ba891a471cb835e9c532be926a7673",
  "version": 1,
  "size": 415,
  "vsize": 388,
  "weight": 1552,
  "locktime": 1026070553,
  "vin": [
      "coinbase": "030ecb0a2cfabe6d6ddc5406c4378d32bde05d3b7d966ee5a6546c116e9b920d8c8564c2cff893a9dd10000000f09f909f082f4632506f6f6c2f0000000000000000000000000000000000000000000000000000000000000000000000000500fac90200",
      "txinwitness": [
      "sequence": 0
  "vout": [

(Its rawtransaction here).

As is apparent, the locktime is bereft of any meaning, since it is above the max block height value of 500'000'000, but with a Unix timestamp at Sun Jul 07 19:35:53 2002 UTC also set in the past.

What is its purpose? Are the mining pools attempting to communicate something?

  • 9
    This is the first time I hear about this, but perhaps it's used as an additional nonce that's easier to increment than the one in the txin? Oct 30, 2021 at 13:25


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