Koller Auktionen

If you're new to Zurich and someone mentions buying a ring "at Koller," they mean Koller Auktionen, the auction house most Swiss dealers point to first when the conversation turns to estate jewellery. It was founded in 1958 by the lawyer Pierre Koller as a small gallery dealing in fine art and antiques, and it is still family run, now under his son Cyril Koller as CEO. The company's own site describes more than sixty years of experience, and Wikipedia calls it the leading auction house in Switzerland, a claim that gets some outside backing from Forbes, which has named Koller among Europe's ten most important auction houses. None of that matters much on its own, but it explains why a vintage Art Deco solitaire or an estate cluster ring with real provenance so often turns up here rather than at a private dealer.

What you get

Koller runs a dedicated jewellery department, one of roughly a dozen specialist divisions that also cover Old Master and contemporary paintings, watches, furniture, carpets, Asian art, and books. Across the whole house it holds something like 80 auctions a year, both in the saleroom and online only, but jewellery gets its own rhythm: four dedicated auctions a year, timed roughly to April, June, October and December, plus an online-only sale slotted in between. For 2026 the pattern holds: an online jewellery sale is scheduled for September 23, and the main saleroom jewellery auction for December 2, alongside watches the day before and other departments selling through the same week. The site runs in English as well as German and French, which matters if your Swiss German is still a work in progress, and every lot in the upcoming sales is catalogued online with photographs and a condition note before you ever have to show up.

The detail that makes this approachable

The part that turns "auction house" from an intimidating trade-only idea into something an ordinary couple can walk into is the viewing. Koller's own FAQ puts it plainly: every auction's lots go on display at the Hardturmstrasse premises in Zurich for several days before the sale, and, in their words, "our previews are open to the public, with no obligation to register to bid." You can turn up, handle a ring you're curious about, and talk to one of the jewellery specialists about condition and likely interest, all without committing to anything. That's a genuinely different experience from browsing a boutique window on Bahnhofstrasse: you get to examine a piece the way a professional buyer would, side by side with people who might actually bid on it that week.

Bidding itself needs a little more paperwork, but nothing that assumes Swiss citizenship or residency. To register, Koller asks for your name, address, phone number and a copy of a passport or other official ID, reviewed by their client services team. If you plan to bid in the room rather than online, you register with staff at least 15 minutes before the auction starts and are handed a bidder number. None of that is specific to Switzerland, which is exactly what an expat buyer needs to know: a foreign passport is enough to get a bidder number.

Costs and what's actually published

This is where I'd rather be upfront about the limits of what Koller discloses online. A buyer's premium is added to every hammer price, and Koller says the exact percentage sits in the auction conditions for that specific sale rather than as one flat number on the general site, so I'm not going to quote a figure I haven't seen for your particular auction. What the FAQ does state clearly is that bidding online during a live saleroom auction (rather than in person or by phone) adds a 3% surcharge, and paying by credit card on a classic saleroom purchase adds a further 3% handling fee; neither applies to the separate ibid online-only sales. If duty or import costs matter to you, for instance because you're planning to leave Switzerland again in a few years and take the ring with you, that isn't addressed on the pages I could read either. It's worth raising directly with the jewellery department before you bid, not after.

On consignment, the opposite side of the business, Koller offers free appraisals: you can send photos or call to arrange a look at a piece, either at home or at one of its offices in Zurich, Geneva, Florence, Munich or Düsseldorf. It also runs periodic valuation days in cities well beyond Switzerland, useful context if you're weighing whether an inherited piece is worth consigning here versus selling privately.

How it compares, and what stands out

Compared with a new-build ring from a Bahnhofstrasse maison, buying at Koller means the story of the piece is already written: an Art Deco setting, a stone that has changed hands before, sometimes a named provenance. The trade-off, as this category's whole premise acknowledges, is that you're relying on Koller's own cataloguing and authentication rather than a manufacturer's warranty. Koller's jewellery department has handled genuinely high-value pieces (a recent unmounted diamond sold for CHF 882,500, and a Burma ruby ring by JAR made CHF 618,000), which says less about typical price points than about the seriousness of the vetting a lot goes through before it's allowed into a Koller catalogue at all. Most engagement ring shoppers will be looking well below that range, but the same specialists and the same condition reports apply at every price level.

Contact for the jewellery department is direct and specific rather than a general inbox: specialists including Jakob Zeijl and Isabelle Koller are named on the site with direct phone lines, which is a small thing but a useful one when you want a real answer about a specific lot rather than a form response.

Who it suits

This fits a buyer who wants a ring with genuine history and doesn't mind a bit of process to get there: registering with ID, watching a preview, understanding that the final price includes a premium on top of the hammer figure. It's less suited to someone who wants a fixed price today and a receipt with a warranty card. If you're an expat only planning to be in Zurich for a few years, the passport-only registration is reassuring, but do ask the department directly about what happens if you want to resell or export the piece later, since that isn't something the general website spells out.

The verdict

Koller Auktionen is the obvious first call in this category for anyone in Zurich curious about a vintage or antique engagement ring, and the open, no-obligation preview days are the reason it's approachable rather than intimidating. The one real caveat is that some of the numbers that matter most to a buyer, the buyer's premium percentage and anything about export duty, live in per-auction documents rather than on the general pages, so budget an email or a phone call to the specialists before you commit to bidding.