* Q2 net profit 413 mln euros vs 353 mln poll forecast
* Expects European Commission decision on state aid soon
* No interim div, keeps cash buffer to repay state aid
* Shrs down 3.6 pct, biggest decliner in insurance index
(Adds CEO, trader comment, shares)
By Gilbert Kreijger
AMSTERDAM, Aug 12 (Reuters) - Insurer Aegon (AEGN.AS) used forecast-beating results to hoard a "sizeable" cash pile in the face of uncertainty on how it will repay Dutch state support and expects a European Commission decision on the aid soon.
Aegon, which reiterated on Thursday it is exploring options for Transamerica Reinsurance including a sale, received 3 billion euros ($3.87 billion) from the state in 2008 at the height of the credit crisis and still needs to pay back two-thirds.
Some analysts believe Aegon, a top-10 life insurer in the United States where it owns Transamerica, may raise capital to pay down the remaining sum, which could carry a 50 percent penalty as well.
Uncertainty over how it can repay the aid weighed on the shares, traders said, while analysts pointed to an unexpected fall of excess capital by 19 percent after Standard & Poor's increased some capital requirements.
"Will it issue shares or not to pay it back? There is uncertainty and that is a guarantee for a negative sentiment," said Jos Renssen, trader at Keijser Capital, adding that Aegon's forecast-beating second-quarter results were good.
Aegon shares were down 3.6 percent at 4.37 euros by 0826 GMT, making them the biggest decliner in the STOXX Europe Insurers Index .SXIP, which fell 0.4 percent.
When asked about the possibility of issuing shares, Aegon Chief Executive Alex Wynaendts told reporters on a conference call: "It is important to get approval from the European Commission. If we get approval we can say more what we will do."
Aegon, which said it kept a "sizeable cash buffer" to repay state aid as soon as feasible, issued shares last year to pay back the first 1 billion euros of aid.
Shareholders' equity has more than doubled over the past 12 months to 17.2 billion euros, helped by retained profits and positive revaluations of investments.
Wynaendts said there was interest from strategic and financial parties to buy Transamerica's reinsurance unit, which most analysts think can be sold for between 1 and 1.5 billion euros to rivals such as Munich Re (MUVGn.DE), Reinsurance Group of America (RGA.N) or Berkshire Hathaway's (BRKa.N) General Re.
Aegon reported a net profit of 413 million euros for the April-to-June period compared with 353 million euros analysts had expected on average in a Reuters poll.
Higher life sales and investment income and a stronger dollar helped push net profit up 11 percent from the first quarter. It lost 161 million euros in the same period last year.
Most life insurers such as U.S. rival MetLife (MET.N) and Britain's Aviva Plc (AV.L) have reported profit growth in the the past month, helped by higer life sales although some, like Canada's Manulife Financial (MFC.TO) and Dutch group ING Groep ING.AS, suffered from weak equity markets and low bond yields. [ID:nLDE6740HV] [ID:nN05195286] (Editing by Marcel Michelson and Michael Shields)