Gold loss-development curves and a widening fan of uncertainty on navy

For students, analysts & credentialed actuaries

The working reference for decisions under uncertainty.

Actuarium pairs a team of specialist AI actuaries with verified calculators, a rigorous library, and a single unified decision method — for pricing, reserving, forecasting, reinsurance, and any choice made before the outcome is known.

The master equation

S(a)=(1ω)[(1ε) ⁣0 ⁣g(PZ{u(Xa)>t})dt+εminsu(xa,s)]ωR(a)\mathcal{S}(a)=(1-\omega)\Big[(1-\varepsilon)\!\int_0^\infty\! g\big(P_{Z}\{u(X_a)>t\}\big)\,dt+\varepsilon\min_{s}u(x_{a,s})\Big]-\omega\,\mathcal{R}(a)

Set g=id, ε=ω=0, u(x)=xg=\mathrm{id},\ \varepsilon=\omega=0,\ u(x)=x and it is expected value; turn the dials and it becomes utility, TVaR, credibility, or minimax regret.

Everything an actuarial team does — done rigorously.

Every formula, rendered and explained.

From the chain-ladder factor to the Mack mean-squared error, the Bühlmann credibility weight, and the Wang transform — Actuarium renders mathematics natively so notation is never a barrier.

Chain-ladder factor

f^k=i=1nkCi,k+1i=1nkCi,k\hat f_k=\frac{\sum_{i=1}^{n-k} C_{i,k+1}}{\sum_{i=1}^{n-k} C_{i,k}}

Bornhuetter–Ferguson

U^iBF=Ci,ni+1+U^i0(11CDFni+1)\hat U_i^{BF}=C_{i,n-i+1}+\hat U_i^{0}\Big(1-\tfrac{1}{\mathrm{CDF}_{n-i+1}}\Big)

Bühlmann credibility

Z=nn+K,K=EPVVHMZ=\frac{n}{n+K},\qquad K=\frac{\mathrm{EPV}}{\mathrm{VHM}}

Tail value-at-risk

TVaRα(X)=11αα1VaRu(X)du\mathrm{TVaR}_\alpha(X)=\frac{1}{1-\alpha}\int_\alpha^1 \mathrm{VaR}_u(X)\,du
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