Hi Paolo,
Yes, I´ve followed him for a while and has very interesting content. It seems he knows all the good tricks. He has a new book called "Los trucos de los ricos" which is good value too.
For what I have found online and from reading the law this is only applicable to companies. It is an special regime that you can choose if you have an S.L that manages long-term rentals (at least 3 years) of at least 8 apartments. Also, at least 55 percent of the value of the S.L.'s assets should be capable of generating income that is entitled to the application of the bonus (art. 49 LIS).
Obviously there are significant monthly operating costs for having an S.L. (around 400 Euros in social security and accountancy fees) so you would need to do the math to make sure the tax savings exceeded the costs for maintaining the S.L. The other thing is you have to pay corporate tax rate (fixed at 25%) and then potentially again depending how you withdraw money from the S.L. for instance tax on dividends. Art. 21 talks about exemptions for tax on dividends but I´m still trying to decipher that one. Either way, I´m sure that Juan Haro will have some clever ways to avoid this double taxation and get money out of the S.L! If you withdraw it as wages, you don´t have to pay corporate tax as well (as wages are a deducible expense) but then you are paying progressive income tax rates.
If you were to rent it out as a particular, the deduction would be up to 60% - so still not bad!
The other important thing to consider is if you intend to move out of Spain at some point. If you cease being a Spanish tax resident, as a particular you lose all ´bonifications´ as well the ability to deduct expenses. As such, you will pay tax on revenue, not profit, meaning you could be making a net loss and still have to pay taxes.
This is my understanding of the situation, but I am still trying to figure it all out myself, so please don´t take any of this as gospel.
I´ll let you know anything else I learn.