Based on the financial facts and market data provided for VERBUND AG, here is the assessment of the extent to which the entity should be advised to issue hybrid bonds in the next 18 months:

1. **Historical Hybrid Issuance:** VERBUND AG has never issued hybrid bonds in the past, and there were no issuances in 2021 or 2022. As indicated by the guidelines, the lack of previous hybrid bond issuance is a very strong indicator that the company does not have a structural or strategic need to introduce them into its capital structure.

2. **Strong Credit Metrics and Leverage Profile:** The company's credit metrics are exceptionally robust. For the fiscal year 2022, the S&P Net Debt / EBITDA ratio stands at a low 1.6x, and the S&P FFO / Net Debt ratio is very strong at 0.5174 (51.74%). This suggests a highly conservative capital structure and strong cash flow generation capabilities relative to its debt load. The company exhibits a very comfortable financial risk profile, likely supporting an "A" range credit rating. 

3. **Operating Performance and Liquidity:** VERBUND AG saw a massive increase in its EBITDA (growing from 1.58 billion EUR in 2021 to 3.16 billion EUR in 2022) and in Cash Flows from Operating Activities (rising to 2.02 billion EUR). With low interest expenses relative to earnings, the company's interest coverage is massive. Although Moody's noted a "Deteriorating" leverage trend, it starts from a position of profound strength, negating any immediate necessity for capital structure optimization through hybrid equity credit. 

4. **Cost of Capital:** In the rising interest rate environment of 2022, issuing subordinated hybrid bonds—which carry a significant premium over senior debt—would unnecessarily increase VERBUND AG's overall cost of capital without providing a required rating defense, since the existing rating headroom is already more than sufficient.

Given the absence of previous hybrid issuance, exceptionally low leverage, massive cash flow generation, and no impending material rating pressure, the company fits the criteria for 0% hybrid capital reliance perfectly.

<answer>0%</answer>