This article first appeared in the special edition of The State of Fashion: Watches and Jewellery, co-published by The Business of Fashion and McKinsey & Company. To learn more and download a copy of the report, click here.

The second-hand luxury watch market, also known as certified pre-owned, or CPO, is on fire. Barely a footnote in the business narrative a decade ago, today it represents 27 percent of all watch sales across the premium to ultra-luxury value segments. By 2025, it is expected global sales will total $29 to $32 billion, more than half the value of the primary market at the time. At first, the pre-owned market presented consumers with few assurances, but many CPO players now offer brand accreditation and warranties that compare with the primary market. Secure, intelligent e-commerce platforms, together with user-friendly valuation and trade-in tools, have further boosted the sector’s legitimacy.

According to Zahra Kassim-Lakha, director of business development and integration at the Richemont-owned specialist CPO retailer Watchfinder, the challenge is now not just to scale the CPO concept, but also to satisfy surging demand. To meet it, Watchfinder trains up watchmakers to service watches and ready them for resale and underwrites trade-ins for primary market players, such as the Richemont-owned IWC and Jaeger-LeCoultre boutiques, as well as multi-brand players like Mr Porter. But, as Kassim-Lakha suggests, fundamentally, pre-owned is still all about trust.

BoF: The pre-owned watch market was once the Wild West. Are those days over?

Zahra Kassim-Lakha: Yes and no. Nobody knows how big the market is [but] it’s growing fast, and there are still grey areas. In the UK, the pre-owned market has become very professional, but there are markets where it’s still the Wild West.

How do you define that professionalism?

There are two vectors. The first is trust and the second is choice and availability. Both are value-added for the customer. Those two vectors will frame market growth.

The CPO market will grow by 8 to 10 percent per year between 2019 and 2025, compared to 1 to 3 percent for the primary watch market. Why is CPO growing so fast?

Until not that long ago, many customers didn’t know you could buy pre-owned watches safely. And they didn’t know they could sell and trade their watches. The market didn’t exist. But now we have this circular economy, which we’re seeing across luxury categories. This dimension is key to the growth of certified pre-owned.

Exports of new Swiss watches are tumbling. Is CPO responsible?

I don’t have data to support that theory, but what I am seeing is a symbiotic relationship between pre-owned and new. We work with brands and retailers on trade-in programmes, underwriting customer trade-ins. This unlocks cash for a customer and is a growth-driver for new.

Is CPO being driven by the sustainability trend?

A watch is a sustainable product, for sure. It’s not disposable. The long-term is built in to luxury purchases. But CPO purchases aren’t driven by guilt. Instead, there’s pleasure in knowing you can buy a watch for under retail [price], and perhaps even a watch no longer in circulation.

Prices for rare, premium pre-owned models are soaring. Will this continue?

Some of this is a bubble created by an international but small group of collectors and press. And there are cycles, just like in art collecting.

Some brands have created their own CPO platforms. Are we going to see more of this?

Brands have already been curating values through the auction market with very little consumer protection, and so some will dabble, yes. Others will want to be front-runners. Our belief is the greater the offer the better, because it brings greater understanding and trust [to the pre-owned market].

What challenges lie ahead for CPO?

The challenges are different for local, national and international players, but scale and scalability is number one. There’s always a supply challenge, and then you have the issue of servicing. The industry needs more watchmakers, which is why we run a service centre and an apprenticeship scheme.

This interview has been edited and condensed.