"Vest sales on Moosejaw.com are absolutely exploding. Up almost 700 percent over the last three years, as we've seen the vest really become the uniform for the finance and tech sectors" Moosejaw CEO Eoin Comerford told CNBC.

Vest sales hit $76.5 million for in June 2018, up 13 percent from the year prior, according The NPD Group Retail Tracking Service.

Sales of the office sweater vest — the casual, fleece variety — are taking off. And data obtained by CNBC show that the jump in sales of what's become the unofficial uniform for the finance bro and tech geek is being driven by sales in California, New York, Connecticut and a handful of other states where those industries are thriving.

The anecdotal evidence was everywhere, but the numbers are in and now it's official.

t's become ubiquitous in Palo Alto and Wall Street, parodied on Instagram and memorialized by the wardrobe department on Showtime's fictional hedgefund drama "Billions" and HBO's "Silicon Valley."

The outwear company Moosejaw, which is owned by Walmart, processes bulk orders for companies that want their logos emblazoned on a vest to give out to employees, clients and at conferences. Guys who aren't lucky enough to get their vest for free can also order directly off Moosejaw's web site. The sleeveless accessory has become a staple wardrobe piece for the dapper office-casual man. The Wall Street Journal officially recognized it as a trend in an article in July: "How the Fleece Vest Became the New Corporate Uniform." All the best dressed economists had them on Friday at the Kansas City Federal Reserve's annual economic symposium in Jackson Hole, Wyoming.

Patagonia is one of Moosejaw's best sellers for corporate clients, Comerford said, "because it says they care about the environment and their employees." The North Face and Arcteryx are also popular, he said. "If they want to be more international, Fjallraven from Europe," he added.

"New York is definitely our number one market for vests. We saw that market explode, actually starting three years ago, over 150 percent growth," Comerford said. It's a similar story in California and other markets, like Massachusetts and Carolina, which he said also have decent tech and finance sectors (as well as strong vest orders).

BMO Capital gave research associate Keith Tapper his company-logoed vest on his first day, he said. Everyone in his office wears them "all year, year-round, it's so cold in the office," he said. "It's like a nice shell, it protects me."

A group of five colleagues at Mitsubishi UFJ Financial Group waiting outside a food truck in midtown Manhattan earlier this week said they all got their Patagonia company-logoed vests on their first day and wear them in the office most of the time.

The vests are also a bit of a status symbol, awarded for good performance, and they're also good for cold trading floors, they said.

But vest sales may be peaking in the country's financial capital, Comerford said.

"New York is reaching saturation," he said. He also explained there's a replacement and upgrade cycle, and new employees in the finance sector are driving current demand.

Dick's Sporting Goods is also seeing strong demand for vests, with New York, Connecticut and California among the top ten states for vests sales.

"Vests continue to be a strong business for us, and we continue to see traction in both fleece and outerwear vests," the company said in a statement to CNBC. Patagonia and North Face are also top sellers, especially Patagonia's fleece Better Sweater Vest made exclusively for Dick's, the company said.

Patagonia was the No. 1 brand ordered in the U.S. between July 1, 2016 and June 30, 2018 with a market share of 57 percent, according to a Rakuten Intelligence scan of millions of email receipts for men's vests. The North Face and L.L. Bean came in at number two and three with market shares of 11.1 and 10.8 percent respectively. Duluth Trading was fourth with more than 7 percent of the market, followed by Uniqlo (owned by Japan's Fast Retailing) at 4.6 percent, Rakuten said.

However, over the last year, Patagonia vest sales fell by about 5 percent, while North Face vest sales grew by the same amount over the same time period, and L.L. Bean vest sales surged 27 percent, according to Rakuten Intelligence.

Grey is the most popular color for the finance industry, and black is the most popular overall, Comerford said. While the most popular season is right around now, Comerford says there is not a huge seasonality for vest popularity, though the holiday season is another important time.

Patagonia, The North Face and Uniqlo declined CNBC's request for comment.