Alpenglow targets 150-millisecond finality. NSCC’s netting reduces equities payment obligations by an average of 98%, addressing a different settlement constraint.
Solana activated Alpenglow on mainnet on Oct. 21 at slot 459,653,000, replacing TowerBFT with a consensus design that targets about 150 milliseconds to finality. Under the new protocol, confirmed and finalized become the same state.
At the National Securities Clearing Corporation (NSCC), multilateral netting cuts the value of equities payment obligations by an average of 98%.
Alpenglow shortens the time until a transaction becomes irreversible, and netting reduces the amount of money participants must move to complete trades.
The first phase of Solana’s Alpenglow upgrade, Votor, has validators exchange votes directly and aggregate them into certificates, which allows finalization in one or two voting rounds. Transaction execution, the Solana Virtual Machine, and fee mechanics stay as they were.
Solana's documentation says production applications read mostly at the confirmed level, and that every confirmed block has historically finalized.
The gain concentrates in workflows that wait for full finality before releasing assets or recognizing settlement.
Solana's documentation cites 12.8 seconds for TowerBFT finality at the older 400-millisecond slot time. Solana cut slots to 200 milliseconds on Oct. 9. Applying TowerBFT’s documented 32-slot finalization rule to that slot time gives a nominal 6.4-second baseline, rather than a measured end-to-end settlement time.
NSCC acts as central counterparty for eligible equities trades, guaranteeing qualifying obligations and offsetting purchases and sales among participants so residual payments settle.
The Depository Trust & Clearing Corporation (DTCC) reports the 98% average reduction in payment value and $608 trillion of equity transactions processed in 2025.
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