The NZX 50 gained 11 points or 0.2% to close at 4759 on Wednesday.
Xero's stock rose more than 7% to hit a new record of $22.10 giving it a market capitalisation of nearly $2.6 billion.
The New Zealand dollar has risen across the board.
At about 5pm it was trading at 83.92 US, 88.11 Australian, 52.54 pence, 0.6210 euro and 82.67 yen.
