It was designed to name and shame those organisations where women were lagging behind and start a conversation that would revolutionise workplaces.
But if the first set of gender pay figures published by big employers was greeted by astonishment at the massive discrepancies at some businesses, the second might be remembered for a lack of progress.
More than half of employers appear to have failed to narrow their pay gaps. So is this any more than a cumbersome box-ticking exercise?
Well, here are five things to take into account:
1: The gender pay gap is not the same as equal pay
Measuring a company's gender pay gap is pretty simple: line up all the male employees in order of salary, do the same for the women, and compare the two in the middle.
So the pay gap isn't just about whether men and women are getting equal pay for equal work (an area that's been covered by law for nearly 50 years).
It's also about how many women are working at a company, and if they're progressing up the ranks
2: That doesn't mean equal pay is necessarily sorted
More than 35,000 equal pay claims were filed at tribunal in the last full year. Increasingly, cases have focused on what constitutes equal work, with claims that fields where women have been traditionally overrepresented have been undervalued.
For example, store workers at Asda and Next are currently arguing that they should be paid the same as colleagues working in warehouses. Encouraging greater pay transparency may have triggered a different way of evaluating work.
3: A widening gender pay gap may actually spell progress
EasyJet has one of the widest pay gaps, because pilots are predominantly men.
Recruiting more female pilots at entry level will cause the gap to widen before they move up the ranks.
It's a reminder that there's no quick fix to the pay gap.
4: Getting more women in the door isn't the whole answer
You also have to stop them leaving. Men and women earn roughly similar salaries in the early parts of their careers; the gap opens up once children arrive.
Some claim this reflects women's choices, that they opt out of career progression or even the workplace - so the gender pay gap is a myth.
However, the Equalities and Human Rights Commission found that one in nine pregnant women had been let go from their jobs, or treated so poorly they felt they had to leave.
And those who choose to return after having a baby may face other challenges; the same survey found a third of employers believed mothers were less interested in career progression.
5: Don't just blame companies
Ask gender pay specialists and they'll tell you there are many initiatives that companies can take - tackling unconscious bias, offering more flexible working and encouraging shared parental leave.
But the issue doesn't end at the office door. The experts say society needs to change.
Schools could encourage girls to take more STEM subjects: science, technology, engineering and maths. There should be more flexible, affordable childcare options. And men could take on more of the household chores.
But gender pay gap reporting may not be enough: the government may need to get tougher.
Critics point out a lack of penalties at present for firms that are failing to make improvements, or even get their figures right (hundreds had to correct their figures after last year's deadline).
Is it all worth it?
Well, over her career, the average woman can expect to earn almost a quarter of a million pounds less than the average man. It's quite a penalty.