Having raised $180 million in capital in October 2013, Xero has experienced an 85% rise in subscription revenue from $28.1 million to $52 million and retains $170.8 million cash in hand to fund future growth.
Its total customer base grew 76%, by 160,000, to 371,000 for the six-month period.
The stock of Xero, which has never posted a profit, soared to $45.99 in March but plunged below $20 in August and fell further after yesterday's announcement, 2.5% to $17.06.
Brokers at both Forsyth Barr and Craigs Investment Partners singled out US sales, customers, staff numbers and business strategies for scrutiny.
Forsyth Barr broker Haley Van Leeuwen said there was nothing in the result to change the ''underperform'' view on Xero stock.
''If anything, the lack of an update on progress with a US chief executive highlights how far Xero must still go in that market ... products that meet the requirements of the market are essential,'' she said.
Xero said yesterday: ''The US is a significant and addressable opportunity with the majority of small businesses unserved by cloud accounting software. Xero is well positioned to meet this need directly through Xero.com and its accounting partners.''
Craigs broker Peter McIntyre said the Xero story revolved around its ramping up of sales.
''From a percentage point of view, they're looking very impressive,'' he said.
However, he noted that the 120% growth in the US - considered the crucial market for Xero - was off a low base, from 10,000 to 22,000 customers, and the UK's 103% was from 30,000 to 61,000 customers.
''The question mark is whether they are growing fast enough in overseas markets,'' Mr McIntyre said.
Australian customer numbers grew 100%, from 79,000 to 158,000, while growth in New Zealand was more ''moderate'', from 86,000 to 119,000.
''There were investor expectations of US growth being higher,'' he said.
Mrs Van Leeuwen estimated the earliest time to see ''meaningful growth'' in the US was in full year 2017, from April 2016 to March 2017.
''In the meantime, headcount and cash-burn continues to grow.''
Xero staff numbers grew 70% from September last year to 993. In September, its North American chief executive, Peter Karpas, left the business after just six months.
The company said about its North America segment: ''Xero did not execute to plan. Key leadership changes are being made in the region and Xero expects to accelerate growth over future periods.''
Xero is eyeing a US listing after it reaches annual revenues of $US100 million, expected in this financial year, and has tapped former Microsoft chief financial officer Chris Liddell as chairman.
