Y-share是指Y股，除了Y-share之外，股票代码以字母Y结尾的股票，也称为Y股。

在Investopedia中，对Y-share有较为详尽的解释，答主在此摘录一些主要信息，供题主参考：

Y-shares are an institutional share class offered in open-end mutual funds. Targeting institutional investors, the share class often has a high minimum investment, beginning at approximately $25,000. This share class also offers the benefit of waived or limited load charges and lower comparative total annual fees.

Example of Y-Shares

Putnam Investments is one investment manager that offers Y-shares across many of its funds as the primary share class for institutional investors. The Putnam Global Equity Fund provides one example. The Fund offers A-shares, B-shares, C-shares, M-shares, R-shares, R6-shares, T-shares, and Y-shares.

The Putnam Global Equity Fund’s Y-share class charges no front-end or back-end sales commissions. The share class also charges no 12b-1 fees, which helps it to have one of the lowest annual expense ratios in the fund. Performance for the Y-shares as of March 31, 2022, was also one of the highest in the Fund for the last five years at 8.92%.

参考译文：

Y股是开放式共同基金中提供的机构股类别。针对机构投资者，股票类别通常有较高的最低投资额，起价约为25,000美元。这种股票类别还提供免除或限制装载费用以及较低的相对总年费的好处。

Y股的实例

Putnam Investments是一家投资管理公司，为其许多基金提供Y股，作为机构投资者的主要股票类别。Putnam全球股票基金就是一个例子。该基金提供A股、B股、C股、M股、R股、R6股、T股和Y股。

Putnam全球股票基金的Y股类别不收取前端或后端销售佣金。股票类别也不收取12b-1费用，这有助于它成为基金中年度费用率最低的类别之一。截至2022年3月31日，Y股的表现也是该基金过去五年来最高的表现之一，为8.92%。