2024 has seen a rollercoaster ride for the JD Sports Fashion (LSE: JD) share price. I hold the FTSE 100 sportswear and trainer retailer in my self-invested personal pension (SIPP) and I’m feeling dizzy, especially today.

I bought JD Sports on 21 January, as the shares plunged after a poor Christmas trading period triggered a profit warning.

The growth stock had outpaced the FTSE 100 for years, and I thought this was my opportunity to get in at a cut-price valuation. Since then I’ve been up and down, up and down, but recent weeks have felt like a ride on the big dipper.

This FTSE 100 stock has given me a bumpy ride

The first major dip came after the Budget hiked employers’ National Insurance rates and the minimum wage. JD Sports chairman Andrew Higginson has been vocal about the damage this will do to profits.

The second dip came today (21 November) with the shares down 16.2% as I write, after the board warned full-year 2024 profits would be at the lower end of its forecast range following a “volatile” October. Bigger discounts, milder weather and consumer caution ahead of the US election hit sales.

There was some respite in Europe, with sales rising 3.5% in the 13 weeks to 2 November. But sales fell 2.4% in the UK, 1.5% in the Americas and 3.8% in Asia Pacific. It’s not a good look.

Q3 like-for-like sales were down just 0.3% overall, while organic group revenue actually climbed by 5.4%. JD Sports is still on course to make annual pre-tax profit of between £995m and £1.035bn, before adjusting items.

Did US consumers really stop buying trainers because there was an election on, as JD claims? I guess they had other things on their mind.

Will the ‘Trump bump’ extend to sportswear? Maybe. But it could also suffer if Trump follows through on threats to slap tariffs on imports to the US. While JD Sports sells US brands like Nike its global supply chain leaves it vulnerable.

This growth stock is falling fast

CEO Regis Schultz says the group “maintained our operating discipline to deliver on our long-term commercial strategy rather than a short-term sales focus”. That’s the right thing to do but doesn’t help if consumers are struggling. Over 12 months, JD Sports shares are down 18.8%.

I bought JD Sports with a long-term view and won’t be selling after today. So should I take advantage of today’s dip to buy more? With the price-to-earnings ratio down to 9.3, it’s tempting. A price-to-sales ratio of 0.6 suggests that I’d pay just 60p for each £1 of sales JD Sports makes.

If I didn’t already own JD Sports, I’d jump at the chance. But I already have enough exposure to its fortunes. Or lately, its misfortunes. So I’ll just hold and hope. Given current economic and political uncertainty, I expect the rollercoaster ride to continue. A lot depends on Christmas now.