Glossary
Key terms used in the AEX platform and New Zealand electricity market.
A
Ask — The lowest price at which a seller is willing to sell. Also called the "offer".
Auction — An opening session where orders are collected and matched at a single clearing price, before continuous trading begins.
B
BASE — A load profile covering all trading periods (24 hours). One of five profiles available on AEX.
BEN — Benmore Grid Exit Point, located in the South Island of New Zealand.
Bid — The highest price at which a buyer is willing to buy.
C
CFD (Contract for Difference) — A financial derivative where parties settle the difference between a contract price and a reference price (typically the spot price) without physical delivery of electricity.
Contract — A tradeable instrument defined by product, delivery period, and expiry. For example, "OTA BASE Apr-26" is a contract for Otahuhu baseload electricity delivering in April 2026.
Credit Limit — The maximum bilateral exposure permitted between two trading entities.
D
Day Order — An order that expires at the end of the current trading session.
Depth — The total quantity of orders resting at a given price level in the order book.
E
Entity — A trading organisation registered on AEX. Each entity has its own users, credit limits, and positions.
EP (Evening Peak) — A load profile covering evening peak trading periods.
F
Fill — A completed trade where a buy order has matched with a sell order.
FOK (Fill or Kill) — A time-in-force setting requiring the entire order to be filled immediately, or cancelled entirely.
G
GTC (Good Till Cancelled) — A time-in-force setting where the order remains active until explicitly cancelled or the contract expires.
GXP (Grid Exit Point) — A point on the New Zealand electricity grid where electricity exits the transmission network. AEX trades at two GXPs: OTA (Otahuhu) and BEN (Benmore).
I
IOC (Immediate or Cancel) — A time-in-force setting where the order matches as much as possible immediately, and any unfilled quantity is cancelled.
L
Limit Order — An order specifying the maximum buy price or minimum sell price. Rests in the order book if not immediately matched.
Lot — The standard unit of trading quantity on AEX.
M
Market Order — An order that executes immediately at the best available price.
MP (Morning Peak) — A load profile covering morning peak trading periods.
MWh (Megawatt hour) — The unit of energy used for pricing on AEX. Prices are quoted in NZD per MWh.
N
NZDT (New Zealand Daylight Time) — UTC+13, observed during daylight saving (last Sunday in September to first Sunday in April).
NZST (New Zealand Standard Time) — UTC+12, observed outside daylight saving.
O
ON (On-peak) — A load profile covering on-peak trading periods.
Order Book — The collection of all resting buy and sell orders for a given contract, organised by price.
OTA — Otahuhu Grid Exit Point, located in the North Island of New Zealand.
P
PEAK — A load profile covering peak trading periods. Broader than ON-peak.
Pre-Open — A market session state where orders can be entered but no matching occurs.
Product — A combination of GXP and load profile. For example, "OTA BASE" is the Otahuhu baseload product. AEX has 10 products (2 GXPs × 5 profiles).
S
Spread — The difference between the best ask and best bid price. A measure of market liquidity.
Settlement — The process of calculating and exchanging payments based on the difference between the contract price and the reference price.
T
TIF (Time in Force) — A setting that determines how long an order remains active. Options: Day, GTC, IOC, FOK.
Trading Period — A half-hour interval used in the New Zealand electricity market.