Custom Bindable Property Type Mismatch

I'm having an issue creating a BindableProperty on a custom view. I used a working piece of code as a template and am nearly positive it's a match but there is still the type mismatch error on the binding.

PortfolioHeaderView Property code:

public static readonly BindableProperty PortfolioHeaderProperty =
            BindableProperty.Create("HeaderModel", typeof(PortfolioHeader), typeof(PortfolioHeaderView), null);

public PortfolioHeader HeaderModel 
        {
            get
            {
                return (PortfolioHeader)GetValue(PortfolioHeaderProperty);
            }
            set
            {
                SetValue(PortfolioHeaderProperty, value);
            }
        }

ViewModel Source:

public class PortfolioLandingViewModel 
    {
        public PortfolioHeader HeaderInfo {get; set;}
    }

XAML in page containing the custom view:

<local:PortfolioHeaderView HeightRequest="300" HorizontalOptions="FillAndExpand" HeaderModel="{Binding HeaderInfo}"/>

Exception:

Position 18:83. Cannot assign property "HeaderModel": type mismatch between "Xamarin.Forms.Binding" and "CSSPMobile.PortfolioHeader"

Not sure why it's giving me the type mismatch, hoping another set of eyes may be able to spot something I'm missing.