SIRIOS CAPITAL MANAGEMENT L P reported MKS INC. (MKSI) in 1 quarterly 13F filing from 2026 Q1 through 2026 Q1. Peak portfolio weight reached 1.18% in 2026 Q1. The latest visible filing shows MKSI at 1.18% of the fund.
This page tracks quarterly shares, estimated market value, portfolio weight, filing dates, and disclosure-aligned stock prices directly from SEC EDGAR 13F filings.
This page is designed to answer the real investor question behind a 13F filing: how meaningful was SIRIOS CAPITAL MANAGEMENT L P's position in MKS INC., and how did that conviction change over time? You can read the holding window, peak weight, latest reported size, disclosure timing, and quarter-by-quarter changes without piecing the story together from raw SEC rows.
MKSI was reported at 1.18% of portfolio in the most recent visible filing.
Peak weight helps separate a token disclosure from a real conviction holding the fund genuinely cared about.
Longer holding windows often tell a very different story from short-lived tactical trades or one-quarter experiments.
Knowing that a fund owned a stock is useful. Knowing whether it was a 0.20% placeholder or a true high-conviction position is where the signal actually starts.
As of 2026 Q2 β sorted by position size
These are the practical questions this page is built to answer before you even open the full history table.
SIRIOS CAPITAL MANAGEMENT L P reported MKSI across 1 quarterly 13F filings, from 2026 Q1 through 2026 Q1.
The largest reported portfolio weight for MKSI was 1.18% in 2026 Q1.
The most recent filing on this page is 2026 Q1, when SIRIOS CAPITAL MANAGEMENT L P reported 42,347 shares, equal to 1.18% of portfolio, with an estimated market value of $9.7M.
The chart compares SIRIOS CAPITAL MANAGEMENT L P's quarterly MKSI portfolio weight with the stock's indexed share price, so you can see whether the fund was building, trimming, or holding the position as price moved.