The Long-Short ‘Big Four’ Explained Simply

Imagine you have a piggy bank, but instead of just one company holding all the coins, there are a few big companies that help people invest using a special trick called "long-short." In this article, we’ll meet four of the biggest players in this space and see how much money they manage. Don’t worry—we’ll keep it super simple!

What Does "Long-Short" Mean?

• Long-short is like betting on two horses at once: you buy (go "long") on a horse you think will win, and you bet against (go "short") a horse you think will lose.
• In investing, it means buying some stocks you like and betting that others will fall in price.
• An SMA (Separately Managed Account) is just a fancy way of saying "your own personalized investment account" that a company runs for you.

Meet the Big Four

Here are the main companies people talk about when they mention the long-short "big four":

1. AQR

• AQR manages $311 billion total (we know this from its official Form ADV paper filed with the government).
• At least $15 billion of that is in its popular long-short SMA called AQR Flex, which started in 2021.
• By the end of 2025, AQR managed $69 billion in long-short assets overall.

2. Quantinno

• Quantinno launched its first long-short SMA for advisors, called DEALS, in 2021.
• It manages over $10 billion in DEALS.
• That $10 billion is about 16% of the $60.9 billion the whole company manages.

3. Aperio

• Aperio doesn’t tell us the exact value of each thing it holds, but it manages $152 billion total (per its Form ADV).
• That’s a huge jump—389.7% more—from $39 billion just 30 months earlier.
• It brought in over $15 billion of new money this year so far.
• About $7.5 billion of that new money is in long-short SMAs.
• Fun fact: Aperio is owned by BlackRock (a very big investment company).

4. Parametric

• Parametric manages over $684 billion (according to its Form ADV2 paper).
• It does not share how much of that is in long-short accounts.
• Parametric is owned by Morgan Stanley (another big company).

Important Point: The "big four" long-short leaders are AQR, Quantinno, Aperio (owned by BlackRock), and Parametric (owned by Morgan Stanley). Other leading vendors include these BlackRock- and Morgan Stanley-owned names too!

Summary

• AQR: $311B total, $15B+ in AQR Flex SMA, $69B long-short by end of 2025.
• Quantinno: $10B+ in DEALS SMA (16% of its $60.9B total).
• Aperio: $152B total, up 389.7% from $39B, $7.5B of $15B new money in long-short SMAs, owned by BlackRock.
• Parametric: $684B+ total, owned by Morgan Stanley, long-short amount not shared.

These four companies show how big and popular long-short investing has become!

FAQ

Q1: What is a long-short SMA?
A: It’s a personal investment account where the company buys stocks they like and bet against ones they don’t—like rooting for and against different teams at the same time.

Q2: Why don’t some companies share their long-short numbers?
A: They just choose not to break out those details in their reports, even if we know their total managed money.

Q3: What does "owned by BlackRock" mean for Aperio?
A: It means the bigger company BlackRock is the boss of Aperio and includes it in its family of businesses.

Q4: Is AQR Flex the same as DEALS?
A: No! AQR Flex is AQR’s long-short SMA; DEALS is Quantinno’s long-short SMA. Both started in 2021 but are from different companies.