The tech start-up news certainly hasn’t tailed off in December. In fact this month has seen one of the most remarkable start-up stories of the year. Or ever in fact.

Needless to say, a lot of current tech start-ups are “fintech” companies – they’re involved in financial technology, in particular all things cryptocurrency and blockchain.

All start-ups hope they have that a disruptive, world-changing tech idea that is going to make their fortune but few can really have expected things to turn out quite like Longfin and Ziddu this week.

Ziddu uses blockchain ledger technology to make micro loans to businesses. Longfin is a fintech start-up that began trading on Nasdaq last week at $5 per share. Its business model is to create new trading systems for commodities. As soon as news got out that it had bought fellow start-up Ziddu, the Longfin stock soared to $126.

Of course this has a lot to do with the current Bitcoin mania, that you can read up about over at Smart Bitcoin Investments, but the fact that start-ups are now being drawn in may prompt quite a few that are currently in stealth mode, to rush to market.

Meanwhile in the (slightly more) real world, phone maker Samsung has asked Renovo Auto, a Silicon Valley start-up, to help it develop an operating system that integrates the software needed to run a fleet of shared driverless vehicles – what we used to call taxis. The operating system needs to work across many different vehicle types without compromising security.

Security in the Internet of Things (IoT) arena has been a hot topic and has put some consumers off IoT products. So brand new start-up Xage has emerged from stealth this month right in the sweet spot where IoT, security and blockchain meet. The company is apparently working with IBM on the Hyperledger Fabric project and there is some involvement with Ethereum technology too. The product is already being used to develop secure smart meter technology.

At the other end of the start-up scale, Ginkgo Bioworks this month added $275m in funding, bringing its total value to over $1bn. The company’s work in yeasts, probiotics and “living medicines” has attracted investors such as Bill Gates.

And finally. Softbank made headlines last month for investing in Uber, or trying to. This month it’s waving a rumored $300m at a dog walking start-up. Wag is fighting its way into the dog services business, competing with more established businesses such as Rover. Neither Softbank nor Wag is willing to comment, but several internet sources are carrying the story. Now if Wag could just arrange to pay the dog walkers in Bitcoin ………