The subscription agreement contains the investor's representations, including eligibility as a professional investor, source of funds and anti-money-laundering confirmations, and binds the investor to the terms of the offering memorandum. Once the money is received and the order accepted, shares are issued and recorded on the register.
In traditional funds subscriptions settle by wire and shares are issued after the money is reconciled to the order, which can take days. Atomic settlement removes that gap.