SIA - I bought 500 shares at $8 and left it untouched since it was dropping continuously. Is it advisable to take up the ex-right shares since the stock price is so low now?

Wow... this is a tough cookie. The best advice I would have given was to cut loss before it went XR. Now you have 2 options

1. If you don't want your shares to get diluted, you can fully subscribe to the rights and MCB.

2. Let it be and invest in other stocks that are fundamentally stronger and will recover faster than airlines when COVID-19 is over

Personally, I'd recommend you to do the latter because it doesn't make sense to keep diging deeper into the hole that is already very far from the ground.

Good luck and cheers !

With the economics and realities facing airlines for this and next few years, why throw good money in after bad money ?