I like that name, "the sunken market"!
下沉: sink, PP sunken
source: 百度
translation from me
所谓下沉市场,
The so-called sunken market,
通常是指三线以下城市、县镇与农村地区的市场。
usually refers to the consumer market of third tier cities, county towns and rural areas,
其覆盖的人口规模和消费规模很大,
which (this market) covers a great number of people whose consumption scope is also large,
社会消费品零售额、网购市场规模、移动支付金额等增长迅速,
the amount of retail sales of consumer goods, the scope of internet sales, the volume of e-payment, are all increasing rapidly,
在我国消费大盘中的地位和作用日益突出。
its importance and effect on China's market index grows daily.
以新能源汽车消费为例,
To take new energy vehicles as an example,
2021年我国新能源汽车成为居民大宗消费的亮点和新增长点,
in 2021 purchases of new energy vehicles became a highlight and a new area of growth,
销量同比增长1.6倍,其中,
the sales volume increased year on year by 1.6 times, among which,
下沉市场贡献了约47%的销量,成为增速最快、潜力最大的细分市场。
the sunken market contributed approximately 47% of the total sales volume
成为增速最快、潜力最大的细分市场。
to become the market segment with fastest growth rate and greatest potential.
Can't find an author for the phrase 市场下沉, seems it just comes from the internet.
市场下沉
market percolation
这个词来自互联网,
This phrase comes from the internet,
市场下沉的意思就是“受众的更广和更深入”,
the meaning of market percolation is: the amplification and deep penetration of the target market ,
用人话来说,
(or) in layman's terms,
假如你原先的市场渠道仅仅覆盖的是一线的互联网白领人群,
suppose your original marketing channels barely cover the top tier white-collar internet users group,
市场下沉后,
after percolating down the market,
你覆盖的人群就还多了四五线城市的小镇青年,
your (market) coverage has increased to include the youth of fourth and fifth tier towns.
再继续下沉,
(if you) continue percolating down,
你的客户群就多了广场舞大妈。
your client group will increase until it (even) covers the dancers in the local square. (i.e. everyone)
这意味着你的受众群体更广了。
This signifies your target market will be much larger.
So, I would translate 下沉市场 to English as "percolation marketing"