Appen Ltd (ASX: APX) shares opened strongly on Tuesday, rising to a new 52-week high of $2.69 shortly after the market open.

This follows yesterday's commencement of trading for 7,812,500 new Appen shares issued under the recent oversubscribed Share Purchase Plan (SPP).

The new shares were offered to investors for $1.92 apiece. This means today's 52-week high delivered an impressive 40% capital gain on paper to those SPP investors.

However, the initial market exuberance did not last long.

After the first hour of trading, Appen shares fell into the red.

The ASX tech share is currently trading at $2.58, down 0.39% for the day.

Appen rips then dips as new SPP stock is traded

Appen's share price lift then drift may reflect some profit-taking among SPP shareholders today.

After all, a 40% capital gain is pretty hard to sit on, especially when this stock has a history of volatility.

The SPP received huge support from investors.

Some investors may have seen a short-term trading opportunity, given the SPP price represented an 11.5% discount when the capital raise was announced in mid-October.

Others would have seen the SPP as an attractive dollar-cost averaging opportunity for a company that is pulling itself out of the ashes after a long winter.

(Back in August 2020, Appen was a tech stock darling trading above $40 per share.)

Appen's CEO and Managing Director, Ryan Kolln, said the strong support from institutional investors for the initial placement was reflective of the company's recent return to profitability.

He also said the support highlighted "confidence in our growth potential as our external environmentdisplays continuous signs of improvement, particularly from generative AI related opportunities".

Appen received the $50 million it wanted from institutional investors under the initial placement before launching the SPP.

Appen received applications for about $20.7 million in shares under the SPP — well above its $5 million target.

The company decided to take advantage of this strong support and increased the size of the SPP to $15 million.

Each shareholder received a minimum allocation of 520 Appen shares (equivalent to $1,000 of new investment). The company conducted a pro-rata scale-back on the rest of the funds offered by investors.

Appen says the proceeds of the capital raise will be used as additional liquidity to fund working capital.

The company says it is pursuing opportunities in the generative artificial intelligence (AI) space.

What's happened to Appen shares this year?

Appen shares have roared 319% higher in the year to date under a long-awaited comeback.

This compares to a 7.7% bump for the S&P/ASX 200 Index (ASX: XJO).

Just four years ago, Appen shares were part of the revered WAAAX group and traded above $40.