Private company
Who owns Rosecrans-Sepulveda Partners 4, LLC (Beach Cities Media Campus)
One company in the researched set discloses a stake in Rosecrans-Sepulveda Partners 4, LLC (Beach Cities Media Campus), worth $67,000 between them. Rosecrans-Sepulveda Partners 4, LLC (Beach Cities Media Campus) is private, so no 13F reports it: a 13F covers exchange listed positions only. These figures exist because each holder disclosed the stake in its own filings.
Rosecrans-Sepulveda Partners 4, LLC (Beach Cities Media Campus) - Profile
- Type
- joint venture
- Based in
- United States
Rosecrans-Sepulveda Partners 4, LLC was the venture behind Beach Cities Media Campus, a 6.4 acre development site at 2021 Rosecrans Avenue on the Rosecrans corridor in El Segundo, California, at the western edge of Continental Park, an 86 acre office and mixed use campus in the South Bay submarket of Los Angeles. The parcel was fully entitled for roughly 275,000 square feet of Class A creative office space together with a studio and production building and small retail buildings, aimed at the media and entertainment tenants clustered in the area, but the scheme was never built. The venture brought together Continental Development Corporation and Mar Ventures, the local developers who assembled and entitled the land, with a capital partner, and on 17 September 2025 it sold the site as a land parcel for a gross price of about 56 million dollars.
Source
Rosecrans-Sepulveda Partners 4, LLC (Beach Cities Media Campus) files nothing with the SEC, so none of this comes from a filer record. The description was written for this site in August 2026 from Boston Properties Buys 50 Percent Interest in Beach Cities Media Campus Joint Venture in El Segundo, California (REBusinessOnline), Beach Cities Media Campus property page (Continental Development Corporation), BXP, Inc. Form 10-Q for the quarter ended 30 September 2025 (SEC EDGAR) and Boston Properties Takes 50 Percent Stake in El Segundo Office and Studio Development (Commercial Observer). The ownership figures below come from the holders' filings instead, and are sourced row by row.
The disclosed stakes
One row per position. Where a holder reports the same company in two share classes, both rows are shown rather than summed, because the class is part of a position's identity.
Where each figure comes from
A private stake has no ownership form behind it, so the source is always the holder's own filing or disclosure. Anything modelled says so, with the arithmetic.
- BXP, Inc. (formerly Boston Properties), as of 30 Jun 2026. 50% joint venture interest in Beach Cities Media Campus. Carrying value $67 thousand at 6/30/2026 vs $272 thousand at 12/31/2025, a near-fully written-down position. source
What this page is not
It is not a complete register. It lists the holders who happen to be inside the researched set and disclosed the stake themselves. A private company can have many other shareholders, and nothing here rules them out: venture investors, founders and employees usually appear in no public filing at all. Percentages are of Rosecrans-Sepulveda Partners 4, LLC (Beach Cities Media Campus) where a holder stated one, and are missing where no holder did.