[united]

They came, they shook the industry, and now it looks like they're done:

Costco Suspends Production of the Kirkland Signature Golf Ball
https://www.mygolfspy.com/costco-sus...ig-production/
A representative of Nassau Golf (originally listed as the manufacturer of the Kirkland Signature Ball on the USGA conforming list) has told MyGolfSpy that Costco purchased overruns of Nassau's European-market-exclusive Quattro ball. There is some indication the sale was made through a third party, and that Nassau may not have been directly involved in the deal. The same source confirms that while the Costco balls have a different core color, the material composition and layer thickness are absolutely identical to the Quattro.

With the initial supply of overruns exhausted, Costco effectively has nothing left to sell.

With Costco selling its version of the Quattro at its cost ($15/dozen), it appears that Nassau is not particularly interested in selling Costco any additional inventory. As you can imagine, there's little interest in allowing Costco to undercut the Quattro with the Quattro, nor is there any desire to see the ball market (including direct-to-consumer brands like Snell, and OEMs such as TaylorMade) undercut either.

I mention TaylorMade in particular because the company's tour balls are produced at the same factory as the Costco/Nassau balls, and there are some indications that production of new TP5 has pushed smaller companies to the back of the production line. Even if Costco otherwise had the capability to produce balls immediately, which it appears it doesn’t, the K-Sig wouldn’t be given priority over larger brands and long-term customers.