Brainchip Holdings Ltd (ASX: BRN) shares enjoyed a remarkable turnaround over the last four months of 2024 amid ongoing market enthusiasm over the growth potential of artificial intelligence (AI).

Brainchip has made early success with its neuromorphic processor, Akida. Akida is intended to mimic the human brain and keep machine learning local to the chip, independent of the cloud.

Although shares in the S&P/ASX 300 Index (ASX: XKO) AI stock have slumped 21.8% in 2025, investors who bought the stock in September will still be sitting on some outsized gains.

How outsized?

I'm glad you asked!

Brainchip shares post sizzling end to 2024

At market close on 11 September, you could have bought Brainchip shares for 16.0 cents each.

Meaning your $8,000 investment would have netted you 50,000 shares (excluding brokerage fees).

At the time of writing today, those same shares are trading for 30.5 cents apiece.

That means the 50,000 shares you bought in September for $8,000 would be worth a cool $15,250 today. Or a gain of 90.6%.

Not bad for five months!

What's been happening with the ASX AI stock?

Brainchip shares have historically been highly volatile and are not suited for the fainthearted.

Shares are up more than 400% over the past five years, but if you'd bought the stock at the February highs three years ago, you'd be nursing losses of more than 80%.

See what I mean?

As for the sizeable pullback in January, that appears to be related to two separate announcements.

On 7 January, Brainchip shares closed down 5.3% after the company announced another capital raise via a Put Option Agreement (POA) with LDA Capital.

Total funding available under the POA was lifted to $140 million, up $37 million.

As the Motley Fool's James Mickleboro pointed out on the day, investors were favouring their sell buttons as, "This appears to have dampened any hopes that the company will be pulling in meaningful revenue any time soon."

The biggest daily losses in 2025 came on 28 January, when Brainchip shares closed the day down a painful 15.4%.

That followed the big share price crash in generative AI chip maker Nvidia Corporation (NASDAQ: NVDA) amid the launch of China's low-cost DeepSeek AI program.

Brainchip also released its quarterly update on the inauspicious day. A three-month period that saw Brainchip shares rocket 63%.

Commenting on the December quarterly results at the time, Brainchip CEO Sean Hehir said:

The December quarter saw several strategically important commercial agreements achieved.

These agreements, while relatively modest in their immediate financial impact, are nonetheless significant as they demonstrate a pathway for revenue generation from royalty-bearing IP sales agreements and from further, deeper commercial partnerships with multi-national defence and aerospace industry contractors.