Rubicon will lay off 19% of its workforce, totaling 125 jobs, completing the reorganization it began in Q2. The company is also lowering its guidance for Q4.

It will be the third ad tech company with an SSP to make large cuts this year. PubMatic laid off 100 last December, and AppNexus laid off 150 in October. OpenX and Index Exchange – both of which claim strong header bidding businesses – appear to be the only SSPs that haven’t made workforce reductions.

The layoffs come one quarter after Rubicon CEO Frank Addante said the company faltered because it was slow to respond to the header bidding trend.

Q3 revenue ticked up 2% to $65.8 million, while advertising spend flowing through the platform declined 1% to $242.8 million.

Rubicon will continue to struggle next quarter. Its Q4 guidance predicts GAAP revenue of $65 million to $75 million, a steep decline from Q4 2015, when it posted GAAP revenue of $94 million and grew 125% from the year before.

As Rubicon attempts to reorient itself due to header bidding, Addante expects "short-term headwinds, long-term tailwinds." Long-term, header bidding could increase the number of impressions Rubicon can bid on. Before Rubicon can reap the benefits, it must first implement header bidding on more publishers’ pages and optimize its tech for the header, not the waterfall.

Header bidding, via the FastLane product, was 13% of revenue in June, 16% of revenue in October and Rubicon expects it to be 20% of revenue by the end of the year.

Two hundred publishers representing 1,000 sites use FastLane, compared to 130 publishers with 750 publishers last quarter.

But win rates are “still too low, and lower than what we see in the waterfall,” said President Greg Raifman. In September, as Rubicon focused on improving FastLane’s speed and optimizing algorithms, win rates doubled. Raifman said FastLane began to deliver CPM increases of 50% to 130% after these optimizations. But it will take another quarter or two to fully tune the product.

Because header bidding unifies the auction, it undermined Rubicon’s dominant position in the waterfall. Plus, Rubicon’s fee structure exacerbated the problem, since ad tech companies with lower fees won more auctions and gained share.

"We established a dominant position in desktop display that was largely unthreatened," Addante said. "That opens up the opportunity to raise pricing over time. We did that."

As part of the reorganization, Rubicon combined its product and engineering teams and hired Google exec Tom Kershaw to lead the consolidated team. Rubicon also combined its buyer and seller clouds into a unified org reporting to Chief Revenue Officer Harry Patz.

But Rubicon also suffered a number of senior executive departures, including international head Jay Stevens in March, CFO Todd Tappin in May and Chief Product Officer Dax Hamman in June. Many employees from the retargeter Chango also left.

Addante admitted Chango “didn’t work out exactly as we thought. … We probably wouldn’t have invested in that asset to the level that we did.”

Now, Rubicon is focused on its sell-side strengths.

Despite stalled growth, Rubicon posted a small profit due to organizational efficiency. The company holds $193.2 million in cash and liquid assets, leading one analyst to speculate that Rubicon might acquire to restart growth.