AltMountain

Washington Harbour Sandbox LLC

Arlington, VA · CIK 2067241 · Managed by Washington Harbour Partners LP
Emerging

Washington Harbour Sandbox LLC is a private equity fund based in Arlington, Virginia. According to its most recent Form D, filed Oct 9, 2026, it has sold $1,000,000 of interests to 11 investors since its first sale in Dec 2024. The minimum investment it accepts from an outside investor is $100,000. It relies on the Section 3(c)(1) exclusion, which limits it to 100 beneficial owners, typically accredited investors. The offering uses Rule 506(b), which does not permit general solicitation. Based on its first sale date and the amount raised, AltMountain classifies it as an emerging manager. Related persons named in the filing include Washington Harbour Partners, LP.

Total raised
$1,000,000Cumulative sales reported on Form D
Investors
11
First sale
Dec 10, 2024
Minimum investment
$100,000
Who can invest
Accredited investorsSection 3(c)(1): up to 100 beneficial owners
Offering exemption
Rule 506(b)No general advertising
Key people and entities
Washington Harbour Partners, LP
Latest Form D
Oct 9, 2026

From SEC filings, not verified. This page republishes the fund's Form D as filed. It is not an offer, solicitation or recommendation, and AltMountain has not reviewed the fund. “Raised” is cumulative sales, not current assets or performance. Returns are not part of SEC filings. Private funds are speculative, illiquid and generally limited to accredited investors or qualified purchasers. Full disclosures · Request a correction

Questions about Washington Harbour Sandbox LLC

What is the minimum investment for Washington Harbour Sandbox LLC?

According to its latest Form D, filed Oct 9, 2026, the minimum investment Washington Harbour Sandbox LLC accepts from an outside investor is $100,000.

Who can invest in Washington Harbour Sandbox LLC?

Washington Harbour Sandbox LLC is generally open only to accredited investors, and it may have no more than 100 beneficial owners because it relies on Section 3(c)(1). It uses Rule 506(b), which does not allow general advertising.

How much has Washington Harbour Sandbox LLC raised?

Washington Harbour Sandbox LLC reports $1,000,000 sold from 11 investors on its Form D filed Oct 9, 2026. This is cumulative sales since the offering began, not current assets or performance.

Where is Washington Harbour Sandbox LLC based?

Washington Harbour Sandbox LLC is based in Arlington, Virginia and is managed by Washington Harbour Partners LP.

When did Washington Harbour Sandbox LLC launch?

Washington Harbour Sandbox LLC reports its first sale in Dec 2024, which makes it an emerging manager by AltMountain's definition (first sale in 2021 or later and under $50 million raised).

Size compared with every private equity fund

Raised more than 46% of the 204 private equity funds based in Virginia, and more than 20% of all 9,142 that report sales.

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