Yamaha NS 1000M Find

Speakers don't have watts.
You could hook 'em up to a couple kilowatt monoblocks and have no problems. Just don't crank it to the clipping / distortion level.

I also have no idea where the manufacturers get the rating attached to a speaker. Sine wave RMS? Some kind of averaging music power?
I'm sure you could feed 'em way more power than 150 each as peaks while the continuous never got above say ...... 20% of max.

Long term listening at hi levels will heat up the drivers from resistive heating. Than they will begin sounding different and may even fail. My understanding is that Pro gear is designed with this continuous beating in mind.

One other parameter besides power handling is sensitivity. I'd expect a 100db sensitive speaker which could handle 100 watts to play more loudly than a 90db speaker which could handle the same 100 watts.

My friend years ago sold these Yamaha's speakers at his store. Asked about him about the power rating, 150 watts is about max.

Great speakers. They are 90dB at 8 ohms. Maximum recommended input is 100W.

Agree with T_bone.
As long as they are working properly, they have a sound more attuned to 'live music' than the typically British and US 'sound' of the speakers ruling at the time they were introduced. You bought a bargain.

Only 100 watts? Well they were hooked up powered by a Mac 2300 amp. Power meters did swing passed 100 watt power reading at times up into around 150 .