Should I buy IAG shares today?
British Airways owner International Consolidated Airlines (LSE: IAG) has been a popular stock this year. On my investment platform, Hargreaves Lansdown, IAG has consistently been one of the most purchased UK shares in 2021. Lets take a look at the investment case. 5G is here  and shares of this sleeping giant could be a great way for you to potentially profit! I can see why investors have been piling into IAG shares recently. For a start, IAG is a classic reopening stock. With Covid-19 vaccines being rolled out rapidly, activity in the travel industry is now picking up. Theres a considerable amount of pent-up demand to fly. After a very challenging 15 months or so, the outlook for IAG is definitely improving. City analysts currently expect IAGs revenue to rise about 33% this year to 10.5bn. Secondly, IAGs share price is still well below where it was before Covid-19. Back in February last year, the share price was above 400p. Today, however, it is still under 200p. I have no doubt that the depressed share price is attracting value hunters. The risks  Digging deeper into the investment case, however, there are a few risks that concern me. The first is the enormous amount of uncertainty that airlines face due to the constantly-changing travel rules. The UKs decision to move Portugal to its amber list last week is a good example of the ever-changing rules. This environment is a nightmare for airline operators such as IAG. While there is so much uncertainty, bookings are likely to remain depressed. For IAG, its a concern that both Spain and the US are on the amber list as these are two of its biggest markets. Speaking of bookings, IAG said in its recent first-quarter results that for the second quarter of the year, it is expecting capacity to be just 25% of what it was in 2019. This suggests that a full recovery is a long way off. Its worth noting that it believes corporate bookings are likely to remain below 2019 for years. Another concern is that fuel prices are rising. Recently, the price of Brent crude oil rose above $70. Airlines typically hedge their fuel costs so they are not exposed to rising fuel prices in the short term. Still, higher fuel costs are the last thing airlines need while they are operating at such a low capacity. Fuel costs are a large part of an airlines expenses, meaning that higher oil prices can greatly impact profits. Finally, I continue to have concerns about the companys balance sheet. IAG recently advised that at the end of March, it had net debt of 11.5bn, up 18.5% from last year. Since then, it has launched an 800m convertible bond. This substantial pile of debt adds significant risk to the investment case. With air travel likely to remain depressed for at least a few years while Covid-19 is lingering, it could be hard for it to generate enough profit to pay the interest on its debt. IAG shares: my move now  Weighing everything up, I think the risks outweigh the potential rewards here. All things considered, I think there are much better stocks I could buy today.