ClearSky Fund IV: A Cybersecurity and Infrastructure Investor's $68.4 Million Filing and How to Pitch the Firm

ClearSky Fund IV LP filed a Form D on November 2, 2026 reporting $68.4 million sold, and a sister vehicle, ClearSky Fund IV International LP, reported $41.5 million, both with Alexander Weiss named as executive officer. They were the two largest venture capital filings of the day. ClearSky is a Florida investor focused on cybersecurity and critical infrastructure, so this profile is useful for security founders looking for specialist capital. It covers what the filings show, what public sources say about the firm, and how to approach it. Where sources disagree, or where we found no public detail, we say so.

What the Filings Show

• ClearSky Fund IV LP: $68.4 million reported sold
• ClearSky Fund IV International LP: $41.5 million reported sold
• Named person on both: Alexander Weiss, executive officer
• Sector tag in our data: generalist or unspecified, which comes from the form and not from the firm's strategy

We do not add the two amounts together. A fund with an international vehicle often runs parallel or feeder structures, and we cannot tell from the filing whether the figures overlap. A Form D shows that a vehicle exists and what it reports as sold. It is not a closing announcement.

The Fund IV Timeline

VC Wire reported on November 29, 2024 that ClearSky was raising up to $500 million for its fourth fund, and said an SEC filing at that time showed the International vehicle had not yet raised money. The new filings are the first amounts we found, so they suggest the raise has been under way for about two years and has reached at least $68.4 million in one vehicle. By our arithmetic, $68.4 million is about 14 percent of the $500 million target, and the two vehicles together, if they do not overlap, would be about 22 percent. We found no announcement of a first or final close.

Who Is Behind ClearSky

• Alexander Weiss is a co-founder and managing partner of ClearSky and sits on its investment committee. Some profiles list him as chief executive, so titles differ by source
• Before ClearSky, he was vice president and chief investment officer at NextEra Energy, where he co-headed the company's venture capital investing
• The firm is based in West Palm Beach, Florida, and one profile says it has operated since 2012 with nearly $1 billion in committed capital

What ClearSky Backs

According to public profiles, ClearSky's security vehicles invest in transformative security solutions, with a focus on cybersecurity, industrial security and critical infrastructure security. A separate line of funds at the firm has focused on energy transition, which fits Weiss's background at an energy utility. One report describes ClearSky and Blackstone investing together in FireEye, a cybersecurity company, though we did not confirm the details.

Earlier Security Fund

Reports in August 2018 said ClearSky raised $244.7 million for its first security fund against a target of $300 million. PitchBook later lists Security Fund I at $323 million, so sources disagree on the final size, and we do not state a single figure. Private equity profiles date the close to around 2019.

Why a Specialist Fund Matters to Security Founders

• Domain knowledge: a firm that has backed security companies for years can judge technical risk and customer demand faster
• Customer access: an investor with ties to utilities and industrial companies can open doors for products sold to critical infrastructure operators
• Larger cheques: a fund targeting up to $500 million can lead growth rounds, not only seed rounds
• Narrow focus: the same specialization means it will pass on companies outside security and infrastructure

How Today's Venture Filings Looked

On November 2, our data shows 26 venture capital vehicles reporting $215.6 million in total, and 3 of them reported $0. ClearSky's $68.4 million alone is about 32 percent of that total by our arithmetic.

• Deal-by-deal or SPV vehicles: 13 filings
• Generalist or unspecified vehicles: 11 filings
• Sector-tagged vehicles: one energy and climate filing and one AI filing

The energy filing was Decisive Point, Standard Nuclear V, LLC, at $19.1 million. We found no public detail on it, so we do not describe its strategy. The next largest generalist funds were HAN Moo LLC at $39.8 million and Steel Atlas Select Fund I at $16.1 million, and we found no public coverage of either.

Who ClearSky Is a Fit For

• Cybersecurity companies selling to enterprises, governments or critical infrastructure operators
• Industrial security and operational technology startups
• Growth-stage security companies that need a large lead cheque
• Companies at the intersection of security and energy, given the firm's background

It is less obviously a fit for consumer apps or companies with no security angle.

What Security Investors Look For

Expect questions about what threat you stop that incumbents miss, how you are sold and who buys, how long sales cycles run, and how you prove detection quality. Be ready to show customer references, retention and how your product fits into a security team's existing tools. In critical infrastructure, expect questions about certifications, deployment in sensitive environments and regulatory exposure.

How to Approach ClearSky

• Get a warm introduction from a portfolio founder, a co-investor or a customer
• Send a short note with what you protect, your traction, the round size and why this firm
• Prepare your data room, check your cap table and model your dilution
• Ask whether the firm expects to be lead investor and what its term sheet includes
• Ask which fund vehicle would invest, since the filings show two Fund IV entities

Questions to Ask Before You Pitch

• What stage and cheque size does Fund IV target?
• Does the firm invest through both the domestic and international vehicles?
• How much is reserved for follow-on investment?
• How does it help portfolio companies reach customers in infrastructure and government?

What We Could Not Confirm

We could not confirm Fund IV's final size, whether the two filings overlap, the fund's strategy split between security and energy, or its investments to date. Check ClearSky's own materials for the latest details.

Browse the investor directory for more active funds, or explore active capital on AngelLinx @ angellinx.ai/register.

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