Meaning:

“二级” literally means “secondary,” and “狗” means “dogs.” Many Chinese young people call themselves “dogs” in a self-mocking way, like “single dogs” for singletons and “overtime dogs” for those forced to work overtime. Similarly, “secondary dogs” refer to “stock analysts who study the secondary market and publish reports for a living.” (A secondary market is a market where investors purchase securities or assets from other investors, rather than from issuing companies themselves.) Using the word “dog” implies that the speaker is unsatisfied with the compensation for their hard work.

Example:

A: 你怎么天天出差？

Nǐ zěnme tiāntiān chūchāi？

Why are you on business trips all the time?

B: 没办法，二级狗就是这么苦命。所以很多二级狗也是单身狗。

Méi bànfǎ，èrjígǒu jiùshì zhème kǔmìng。Suǒyǐ hěnduō èrjígǒu yěshì dānshēngǒu。

I can’t do anything about it, and that’s the sad life of a secondary market stock analyst. It also explains why many of us remain single.