"The US is the key to Xero being able to justify its share price so if US investors are going in it gives some confidence to that viewpoint," Harvey-Green said.
Chief executive Rod Drury said on Monday that the new capital was "money in the tank" for Xero to build its United States-based management team.
"We find talent follows money and talent follows talent ... it's a massive war chest and it means we can hire the very best people," Drury said.
The company expects operating revenue for the six months to September 30 to exceed $30.3 million, up 84 per cent from the year before.
Xero's paying customers grew to 211,300 by September 30, 89 per cent up on the same time a year earlier.
In its last annual result, the company posted a net loss of $14.4 million for the year to March 31.
This grew from a loss of $7.9 million a year earlier.