BillPin, a bill-sharing startup out of Singapore that launched to the public 6 weeks ago, has done something rather unique after it completed the undisclosed acquisition of BillMonk, a 2005-founded US company that served as the the inspiration for the BillPin service.

Both services help friends keep up with shared bills and money owed to each other. The deal will see BillPin transition BillMonk’s undisclosed userbase over to its own service, which includes a Web platform and apps for iOS and Android, but none of BillMonk’s staff will move over.

It isn’t every day that a spring chicken of a company buys a comparative veteran, or, indeed, that an Asian startup acquires an American rival, but that is what’s happened in this case. The deal says plenty about the ambition of the BillPin team, who include CEO Darius Cheung, who sold his previous startup tenCube to McAfee in 2010.

The deal is frustratingly scant on raw details, however. The price is undisclosed, and neither Obopay — which bought BillMonk from its founders Gaurav Oberoi and Chuck Groom in 2007 — nor BillPin will reveal the total number of users on the BillMonk service. Cheung does say that BillMonk has around 50 times that of BillPin’s customer base, but given BillPin’s youth, that doesn’t provide much color.

Reminding us that BillPin is entirely self-funded has raised only SG$50,000 (via the i.Jam initiative from Singapore’s government) — and is therefore not exactly flushed with cash like, say Cisco – Cheung says that the team was “in the right place at the right time to get a great deal”.

So why is the deal happening?

Cheung explained to TNW that BillMonk was both the inspiration and reason for BillPin’s inception, but the lack of resources put into it in recent times have seen it deteriorate from its past glory. In essence, BillPin is stepping in to take over.

“We [BillPin's founders] were BillMonk users as students, we love this product. There are very few services that are still being used 7 years after their launch, even despite few updates. BillMonk’s user base continued to grow up until last year, when it began suffering severe downtime. BillPin was initially a hobby to get over those issues of service, and, as we found that lots of others users needed a place to go, we thought: ‘Why don’t we go talk to them [Obopay] to see if we can take over’ – this is the result.”

BillPin launched on February 21 and, while Cheung won’t reveal total user numbers for now, he says the team are “pretty happy with our growth”, which has been around 9 percent per week. The US, India and Singapore are its top three markets, respectively.

Not only is BillPin providing a more stable platform for BillMonk users but, having acquired the company’s assets, IP and infrastructure, it can also analyze 7-years of records, which Cheung says will be ”useful in the long run” to help identify trends and ways to improve the service. For now though, the only plan is to offer a migration path for BillMonk’s likely frustrated users.

In the more immediate future, Cheung says there are plans afoot to raise funding. He anticipates that a seed-stage round is on the horizon, consisting of angel investors across the US and Singapore. Such a move will “help to promote traction” of the service, he says.

BillPin is aiming to raise its round in the usual way, but it has also turned to AngelList — where it has a presence – to explore the potential of connecting with other investors to supplement that.

Related: BillPin is a handy app to split bills between friends and keep track of who owes what

Headline image via patpitchaya / Shutterstock