It was a long wait, but GSK (LSE: GSK) shares are finally in demand. And when I say long, I mean long. Yesterday (April 17) the company’s share price was 2,125p. Incredibly, this is the highest since November 2000 FTSE100 the pharmaceutical giant just changed its name to GlaxoSmithKline and peaked at 2048p.

At the time, GlaxoSmithKline was seen as one of the most solid and reliable dividend stocks in the blue-chip index. A yield of 5-6% seemed certain, with share prices continuing to rise. The stock then fell as the dot-com boom ended, and by 2004 it had dropped by about half. Progress since then has been patchy.

Until recently, the stock price remained near its lowest level in 10 years. Suddenly it changed.

Big FTSE 100 seller

Last week, GSK shares were currently the most popular stock among British investors, accounting for 5.46% of all purchases on the exchange. AJ Bell platform. This is more than twice as much as second place Legal and generalwith only 2.63%. It also overtook gigantic sellers such as Microsoft, Rolls-Royce, BAE systems, Nvidia AND BP. So what’s driving this growth?

It’s not about breaking news. GSK hasn’t released any reports since February 4, when it posted a powerful set of results. Full-year sales rose 7% to £32.7 billion, while underlying operating profit rose 11% to £9.8 billion, slightly above expectations.

New chief executive Luke Miels maintained the growth targets set by predecessor Emma Walmsley, forecasting sales of £40 billion by 2031.

GSK has struggled for years as it tries to replenish its pipeline of medicines after a series of blockbuster treatments fell off patent. To fund this investment, Walmsley has frozen its dividend at 80p per share for eight long years until 2022. This dismal episode culminated in a cut to 57.75p instead of the expected enhance.

We have seen some significant dividend increases, bringing the full-year 2025 payout to 60.6p. Further growth looks possible, with free cash flow jumping 41% to £4 billion.

Dividends and growth

Income seekers may be disappointed with the current yield of around 3.1%, but that’s partly because the share price has performed so well. Over the last year, GSK has grown an impressive 56%. Personally, I’m delighted with this as I bought it two years ago.

GSK looks built for volatile times like today. I understand why there is a demand for this. The valuation remains reasonable, with a price-to-earnings ratio of 12.3 (when I bought it, it looked like a terrible bargain with a P/E ratio of 8).

It also brought a number of clinical successes that further increased demand from investors. However, as with any stock, there are still risks. Like all pharmaceutical companies, GSK is under constant pressure to develop recent treatments and vaccines. However, this process is lengthy and late-stage failures are always a risk.

The sector is also under pressure from governments to lower drug prices. Concerns about U.S. tariffs remain, as does the risk of class action lawsuits.

Still, GSK delivered. For investors with a long-term view, this still seems worth considering. But after such a powerful run, anyone who buys today should be ready for a period of slower progress.