```python
from fastapi import FastAPI

import helpers
import asyncio

app = FastAPI()


@app.get("/portfolio")
async def get_portfolio(symbols: str):
    symbol_list = symbols.split(',')
    tasks = [helpers.afetch_price(s) for s in symbol_list]
    results = await asyncio.gather(*tasks)
    prices_dict = {s: p for s, p in zip(symbol_list, results)}
    return {"prices": prices_dict}
```